Bitcoin Forum

I am considering making some sort of promotional Casascius Coin meant for people to give away.  This coin would be as cheap as possible.

One idea I came up with, was to make a 0.1 BTC real physical bitcoin, but with no security.  It would be colored aluminum, the front would look the same as my other coins, the back would be laser-etched with both the public key and private key in plain sight, along with the message "valid only until redeemed".  There would be no hologram sticker - basically, the first person to redeem the coin gets it.  It would be meant only to be given amongst trusted parties as a conversation starter - not as a serious medium of exchange.

The public key would be a QR code to facilitate easy checking of the balance.  The private key would be printed in alphanumeric plaintext to make it difficult for someone to quickly redeem a large quantity of them.

The idea would be that I can manufacture these in bulk and you can order them by the roll.  People who have never heard of bitcoin would probably be happy to own "some" bitcoin (even if it's a token amount).  These would be machine-made, not hand-made.

What color would it be? And do you have any approximate price per roll/unit in mind?  I think I'd buy a few.

I think this is a GREAT idea. This could work as a massive promotion tool for Bitcoin. If you get the price right, I might just order a large amount. I've already used the 1 BTC coins as gifts but those are not something I give to random people, only to people I know. But the 0.1 BTC coins could be used in street campaigns to get people interested.

I also like the idea, but I think that it would be better if there was a simpler/faster way of redeeming the coin. Why don't you use the mini-key format?

+1

I'd definitely buy some.

I think it's a really cool idea, but how much would the addition of holograms add to the price? I feel like the allure of cracking open the piggy bank, so to speak, is part of the appeal of the coins. I just think that it would make new users, particularly those who aren't too tech-savvy, feel like hackers and pique their interest some more.

It depends on the markup, but yes I would be intersted.

Adding the holograms isn't so much the hard part, it's the sticking them on by hand and the security controls that have to go with it.

Way different than if I can just jam a tray of tokens into a laser engraving machine and have a batch of hundreds of them done just like microwaving a TV dinner.

I hear you on the hand placing the holograms. Once when I was 13, I took a job at a local artisan printing press. My duty was to paint a few little spots two different colors on a little accent and the first letter of a Gaelic poem. There were 6000 of them. It was so friggin' tedious.

Out of curiosity, what additional security controls go with the holograms? I just kind of figured that a hologram made to show tampering was placed over the private key and that was that.

  Excellent idea.

  Quick question. Would it make sense to print 'Not Intended For Exchange' or similar on them to make it clear they are one time use? Or would that possibly confuse uniniated recipients about their value?

I ordered 1BTC coins right because of giveaway to people who I'm introducing to bitcoins. As I'm not organizing big sessions where I need to give away tens or hundreds coins, I don't care about 1BTC per coin; I appreciate that they come with some security (hologram), they looks nice and presentee knows that this coin have some value. So - no, I'm not a target audience for buying 0.1 coins...

I think it would be interesting.

How about just 1 BTC coins at less than 85% markup?  That's ridiculous.  1 BTC isn't too much to give away, but why should I pay you 0.85 BTC to do it?

85 bitcents for low volume emission of hand-made coins, with current  btc price? Not bad at all.

Maybe I'll buy some if he keeps the markup at $2 when Bitcoin hits $30 again.

I kind of agree with you. 1 bitcoin is not that much and if the price trend continues, 0.1 bitcoins will become meaningless. Maybe a scratch off card (https://bitcointalk.org/index.php?topic=51978.msg620154#msg620154) would be a better redeemable gift. It would probably be cheaper to make and easier to see whether the coins are redeemed or not.

I think that Casascius is tired of making all those coins by hand and wants to get a machine that does all the work :P

I would buy a few. Make all kinds of neat colors!

Sounds like a good idea to me, I'd probably buy some. 

I'm definitely going to buy some 1BTC coins as Christmas presents next week. I think they'll be appreciated as well as make for some good conversation with the family!

(Do you do discount for forum members?  ;))

Honestly, I think your current 1 BTC coins are far better suited for that. Its still cheap enough that you can give it away (certainly at current bitcoin prices), it looks terrific, the hologram adds some "mystery" "techno".. dont know what, sci-fi aspect to it, and its reasonably secure. Because of the tamper proof hologram and the public/private key, its also a good way to educate people. Having a visible private key and a good chance the coin is worthless, I think will only reinforce any impression that bitcoin is "dangerous" and potentially worthless.

So no, I wouldnt buy any. But Im pooling another purchase for a lot of 1 BTC coins.

For 'giveaway' coins with no privkey security, the denomination is less important to me than the purchase overhead.  If the overhead was extremely low, I'd buy 0.1, 1, even 5BTC coins to give away, depending on the audience. 

I do think that the scratch-off for a private key would be cheaper and would help get the idea across better. I've considered trying to make some myself for circulation at work amongst my office, but haven't gotten any further than the idea yet. If lotteries consider them secure enough for scratch tickets, I would think that it ought to work well for the lower-denomination "bills" (in the 0.1 to 1 BTC range), if one could find a way to manufacturer them cheaply enough.

Scratch off stickers are cheap and common. You can get them at office supply stores.

Yes, if the overhead price was low enough.

Put it this way - I'd buy 10 for 2BTC.  Not sure if that's even reasonable because I don't know what your production costs are, but I'd do it for sure at that price, and maybe at a higher price.

After all the feedback, here is what I am thinking.

1. The giveaway coin should perhaps be 1 BTC, so the production costs can be much lower than the face value.

2. I should use the 22-character private key.

3. I should use or provide round gold scratchoff stickers (even if that meant I just threw the stickers in, and you stick them yourself).

I have ordered some sample aluminum coins from the coin minting company to see how well I can engrave on the colored aluminum with the equipment I have available.  My belief is that I can go straight from an SQL database to the laser engraver so I can blow out thousands of coins a day - as long as the laser can make an impression on these coins (it won't do jack squat on my brass or gold coins without a coating of chemicals).

What color, gold?
That would be col to do some coins that are silver with a colored plastic border.

I think tossing the stickers or holograms or whatever in the envelope with the coins is just fine, the point is the security. If I received one of these with no clue what bitcoin was, I would probably keep the unadulterated coin and do my research without pulling the sticker. If I was sold, I would be very likely to pay it forward and give it to someone else to hook them. Seriously, this is a great idea.

As far as value, it would be nice to have something where your average joe could order a hundred without breaking the bank. I might pick up five or six 1btc coins to contribute to spreading the word, but if they were .1btc coins, I would be getting 50 or 60 (assuming the cost is low enough). Consider the adoption rate of fringe technology like this and the numbers game might be the way to go.

Unless your laser is more than 45w you're not going to touch aluminum either, unless you were to spray them with powdered grpahite and then clean them off in a mild chemical bath afterwards(1% h2o2)

Uhhh, bad idea to just provide the hologram as an extra.  That ruins your whole security process!  A person could order a bunch of these, copy the private keys, then stick the holograms on them and sell them as "unused", when in fact, they are used.  Now, you mention that you would be potentially using aluminum for these giveaway coins, which would mitigate the problem of used coins being sold as unused, at least for people who are already familiar with the coins.

But, a far greater risk is that of people buying "real" casascius coins, peeling off the hologram, stashing the BTC elsewhere, then buying a bunch of these giveaway coins to use the hologram stickers on the "real" coins.  Suddenly, a person can't trust any casascius coins, because they have no idea if the person using them has already spent the BTC and simply replaced the hologram.

If I'm wrong, tell me.  Maybe there's something I'm missing.

FWIW, I would not buy 1 BTC coins for giveaway.  Maybe I'm just poorer than the other folks here, but I just don't have that kind of money to spend.  I would much prefer smaller coins.  Though, again, it depends how much it would cost per coin.

I think the talk is of some different, 'scratch-off' sticker, so the overlap with the fancy coins won't be an issue. I was the one who brought up holograms again, but your point never even crossed my mind. That would create some confusion for sure. Scammers gonna scam, and giving them the tools to do so isn't a good plan.

Ok, so both the sticker and the coin are different.  Is the gold scratch off sticker not hologrammed?  That should be enough difference, IMO, to differentiate the two.  Basically, if someone would get confused by a gold scratch-off sticker stuck on a "real" coin, then they'd probably get confused by any random hologram or sticker that a scammer could purchase.

http://www.scratchoffworks.com/
http://www.promoprintinggroup.com/custom.htm

Apparently scratch-off printing is done by a ton of places and is not too cost prohibitive. Sounds like a real fancy state-lottery quality (gloss and UV coating) scratcher is around $0.18 each in a 5000 lot, plus design and shipping costs. Not free, but not too terrible.

The first company I linked does gift and phone cards too. Maybe something like that loaded with .1 or .5btc could be a good promotional item if the coins end up being cost prohibitive. They have got to be pretty damn cheap, because I was buying phone cards for less than a buck all the time when I lived in Panama. You could also choose between the flimsy plastic card and then the thicker credit-style cards.

The only issue with that is what if someone at the printer figures out what they are and cashes them all in.  Now if the key was encrypted with a passphrase that you were given when you ordered (and you could write on the card when you gave it out).  You would need client support to make redeeming easy, but I think that would ensure the security of the private key.

The only thing wrong is the misunderstanding that I'd give out my holograms.  I did mention "gold scratchoff stickers".  By that, I mean the kind you can easily find via Google, the kind you can scratch with a coin to reveal what's underneath.

When I first investigated it, I looked at http://www.pollardbanknote.com.

They make lottery tickets.  Apparently they have some kind of controls to account for the security of what's under the scratchoff.  I assume it maybe works something like registered mail, where there's documented control and custody of all the secret data at every step of the process.

Presumably, an acceptable set of controls might be an arrangement where they generate the secrets using a program you provide, and then they agree in writing to be accountable for any compromises.  If they generate the secrets, not even the person ordering the tickets should be able to compromise them.  Therefore, any occurrence of an intact ticket where the value underneath has been redeemed should be prima facie evidence of a compromise.

But I don't really know if that's how they work.  Bitcoin is different from a lottery.  With a lottery, only a few privileged people are able to make use of secrets (e.g. a retailer who can sort the winning tickets from the losers out of his inventory)... on the other hand, with bitcoin, anyone with the secrets can steal the funds, so the controls applied to lottery tickets may not be enough.

What you want though ideally, regardless of how it is done, is exactly ONE entity who could be held responsible for a theft, and who can also afford the responsibility.

Somewhat off-topic, but on a new series of coin it would be cool to have the public key inscribed around the edge of the coin (edge-incused), something like this:

https://i.imgur.com/KNGSc.jpg

For low security, give away coins, I wouldn't put the public address on the coin, only private. Public/Private keys imply a level of security, which is too high for this.

Run a vanitygen so that all private keys equate to public keys '1NoSend...' so that people know that these addresses were created in a low security environment for newbies, and not to fund these addresses. Even Grandma would be able to understand if her account started '1NoSend...' to not put money in it.

Now, a newbie would see the private key and ask himself "if only there was a way that I could fund an address without giving away the private key...", which leads to the understanding of public/private technology.

edit: have your website be able to sweep these (and only these) private keys to a public address of their choosing, or to check balance.

If there were a way to easily scan a public/private keypair into a smartphone app, I would be able to give away small coins and would gain the trust and confidence of the consumer. I could then sell larger amounts of coins, bills, or whatever. QED. Selling them for a markup would be easy and if folks want gold plated collectable Casascius coins, so much the better. I know these apps are coming. Maybe there will be one under my tree this year.  :D

Please reconsider the 0.1 coins or let's go for a compromise and say 0.5. I don't think many of us would want to buy large amounts of unsecure 1 btc coins for mass giveaway. The 1 btc coins you already provide are great gifts but they are not suited for mass giveaway and neither are any other type of 1 btc coin.

Also it's very unlikely that Bitcoin will stay at such low price forever so the 1 btc coins might not be so "cheap" in 6 months.

Would it be possible to put the private key as a QR code on the coin? This would make it much easier to redeem.

Instead of denominating them, maybe I ought to just put "BITCOIN".

I probably will not vanitygen.  It is difficult to vanitygen with mini private keys.

I will probably print only the firstbits and put them in a mini QR code. To me, loading batches efficiently is more important than redeeming a batch quickly.  These are meant as giveaways, QR coding the private key is inconsistent with that purpose and also this is a coin - space is quite limited.

Is there a website that explains in detail how one actually redeems the BTC from a coin?  Somewhere we can refer coin recipients to?  Perhaps have a link to it on the Casascius page so someone who has no knowledge of Bitcoin what so ever but ended up with a coin in their hand, can figure out what to do with it (or simply learn what they 'could' do with it).  Ideally it would be one of the first results to come up when someone Googles Casascius:  "How to redeem Bitcoin from a Casascius Coin" or something along those lines.

EDIT:  And YES, I would absolutely buy 10 bitcent coins.  Given the opportunity, I'd pre-order at least 100 of them right now.

Using firstbits is a good idea, though I'm biased.

What about just letting the purchaser load them up?  If they have the firstbits, it'd be easy enough to quickly type that in, grab the full address, and send 0.1, 0.5 or 1 BTC to it.

Then again, people wouldn't know how much was on it just by looking at it, so you couldn't say it was a 10 bitcents coin or a 1 bitcoin coin - they would all be different.

What can you actually do with 0.1 bitcoin?  Is there any way to spend or withdraw such a small amount?  If it's not a usable/transferrable amount of currency, I don't really understand the point.  If you think people will become "invested" in BTC when you give them half a postage stamp's worth, that's not the way the world works.

It's a token amount to start a conversation / get them interested.

I would probably sell them by the roll of 50, offering to pre-load them in advance, or to generate a list for the buyer to post-load them, or offering to post-load them myself.

Empty coins don't have searchable firstbits, and those not familiar with the command line interface or the "sendmany" command will spend a lot of time loading coins, and will pay a lot of transaction fees.

People wouldn't necessarily know what the amount is, but if the coin says "BITCOIN" it's reasonable to assume it might be 1 bitcoin, without actually having to be.  Presumably if you're talking to somebody about Bitcoin, you'll probably tell them whether you're giving them a whole bitcoin or just part of one.

Eh, good point.  You'd have to send them at least a satoshi before they have firstbits...

Sounds like a good plan though.  ;)

+10

What if you offered two different rates for preloads and empties?

I think you should stick to 0.1 btc. I would buy at least 100 of them if not more. And you should preload them all. Doesn't make sense for people to load them themselves.

And please put on your website information for people who received these coins and just googled casascius.

Do you mean something more detailed than go to MtGox, click "Add Funds", and choose "Redeem Private Key"?

The alternative involves patching source code and is a billion times more difficult.  It's out of reach for the average user.

Another method is to use StrongCoin to import the mini key and then send those coins somewhere else. Having a website that explains to average joe what Casascius coins are and how to redeem them would be very helpful.

This.StrongCoin has been mentioned already.  pywallet might be another option.

We'll wait for it. I appreciate Magic the Gathering Online Exchange for their hard work, but then again I'm a geek at heart. I will use their service for what I can, but they are too slow and complex for most people.


The online services are vital and have a lot of potential, but there needs to be a basic way to import into a simple client.

Bottom line, private key importing needs to be in the default/official client. And the sooner the better.

I have proposed sweepprivkey on the Wiki, which I believe will become the fundamental underpinning for redeeming Casascius coins and any other kinds of physical bitcoins.

With that function properly implemented, redeeming Casascius coins can be as easy as using a Javascript redeemer that initiates a sweepprivkey on a hosted service.  And fortunately, I have seen posts from Gavin suggesting he understands that sweepprivkey is an important function, possibly more so than importprivkey (this was in a discussion about importprivkey).  That right there will probably be the biggest ticket to widespread redeemability.

Ultimately, a customer should be able to redeem the private key on the website he wants to spend them.  God forbid, if he wants to use his physical bitcoin on Silk Road, he should be able to type his private key straight into Silk Road and have it deposited into his balance (assuming that's how they work there).  Sweepprivkey would enable that for any and all websites that accept bitcoin deposits.

The Javascript redeemer sweepprivkey on a host is a great idea as long as it doesn't require setting up an account. It should be done anonymously, even if a fee is taken.

AFAIK, thats not how it works there. As on most websites you dont have a balance, you trade directly with the buyers/sellers.
I also cant imagine ordering some munchies or alpaca socks or even space cake and typing in codes of one coin after the other.
4x 1BTC coins and 12 BTC cents lol, we are going to need that small change after all :)

Anyway, the logical way is importing them in the official client. That would be awesome. Mt Gox is not a solution IMO, not for 1 BTC coins at least. No one if going to sell 1 BTC on MT Gox. I would also like to think these coins have more enduring value than possibly Mt Gox, so some generic way, no matter how complicated for now, would be nice. Just so people see it can be done, even if Casascius and Mt Gox are no longer there, that their bitcoin value doesnt depend on it.

Also, as I requested before, some generic information would be very useful. Id really like to point my recipients to one single page that explains how the coin works, how to redeem it, what bitcoin, where they can spend them etc. Now I have to tell them, go here to redeem the value, there to see what a bitcoin is, oh and over there to find out how the Casascius coin works. A single (brief) page with all that key information would be great. Just put yourself in the shoes of someone who received such a coin and has no idea what it is. Christmas dinners dont last long enough to explain all that :p.

Just a thought, as a promotional tool I think of the handing out at large gatherings scenario like occupy movements.  Being that the private key is not hidden, they could be coins or they could be printed on cards.  I think some people will really get it, some will kinda get it and some won't get it at all and throw them away.  This being the case I think it might be a good idea to print/mint up a version that has an expiration date and if the btc hasn't been spent by that date the btc will be redeemed by the issuer.  If this is printed on the coin or card it is understood and not dubious considering this is for promotional use anyway.  The card could also have more information on it.  Thoughts?

Found the wiki page (https://en.bitcoin.it/wiki/Sweepprivkey_proposal). Thanks. Sweepprivkey looks like a very useful piece of functionality, much more so than importprivkey, since it would also allow the user to redeem their private keys (without importing them).

There is already such a project that does more or less that. BUt honestly, how many people are going to redeem 0.1 BTC?
And then what, they have 0.1 BTC in their wallet, only took them a day to download the blockchain and/or 20 minutes to setup a mt gox account,  12 attempts to get the numbers right. What can they do with it? Nothing. I just dont see it.

0.1 BTC might have some purpose if you speculate on long term appreciation. It might one day become worth enough to bother, but making them expire in x weeks, you might as well save yourself the trouble.

I think it's perfectly okay for people to toss them right now. It would be a 20 cents conversation starter. It would do a lot to help promote Bitcoin IMO. And if they do toss them, so what? It's just 0.1 btc lost forever. But imagine the day when 0.1btc is worth something and people started finding them in couches. That would be funny.

Yes, exactly this.

The point of them is, it's a cheap conversation piece.  Even if they were worth 5 BTC each, some people would never bother to redeem them.  But the fact that it has SOME value, regardless of the AMOUNT of value, piques people's interest.  Those people will be interested whether it's only 0.1 BTC or whether it is 5 BTC.

And people who want to give away 1 BTC coins can just buy the "real deal" casascius coins and give those away.  There's no reason those coins couldn't be used in the same manner.

I wouldnt be amused finding out the coin expired years ago, as suggested in the post I replied to ;)

What about a 0.01 BTC dabloon to be thrown out at Martis Gras parade? People collect them like crazy.

What's the cheapest we could get a token for?

+1

Just to be clear; I dont really oppose the idea of 0.1 BTC coins (though I think the 'full option' 1BTC coins make more sense, but choice is good), I just oppose the idea of making those coins expire , particularly if they expire long before they've had any chance to appreciate in value enough to make redeeming more than just an exercise in futility.

I disagree with them expiring.  It might introduce someone to Bitcoins if they find a discarded coin years down the road, and think, "hey, I wonder what this is?", then find out that they now own 0.1 BTC.

I clicked "Depends on price", but I wouldn't want a lot of them. the hologram seal really is the cool feature of these coins, making them valuable.

I'm really waiting for the new series of 1 BTC coins. I wanted to buy a lot of the old ones at 1.20+shipping, but the price was raised and I ended up waiting for the new series. Even if Bitcoin should rise by quite a bit again, they're valuable enough to be cool but cheap enough to give away every now and then (though not at 1.80 a piece, that's too much for me).

So if the choice is to either do a cheap one or focus on the new 1 BTC series, please focus on the new 1 BTC series! 8) That's what people are waiting for. And that's what I would use to get people into Bitcoin, given that they are reasonably priced.

I think the private key should be covered by a hologram or a scratch-off label or something, and they should have no expiry.

I would cover them with a hologram, but they would be too easy to read with any kind of ray that is reflected by the metal.  The engraving would change the shape of the metal and would be detectable.  So the hologram would be poor assurance that the key has not been read.

Compare to my regular coins - I am using inkjet on paper - which I think would be much more difficult to read from the outside.

Hmmm.  Would some type of metallic hologram help with that?  How about printing the privkey on the coin somehow instead of engraving it?

Interesting, didn't know you used inkjet on paper.  Does that mean the coins aren't waterproof, or does the hologram hold a seal good enough to assure that the paper doesn't get wet?

On the upside, it means that the hologram couldn't easily be floated off the coin without leaving a trace - you'd also ruin the private key on the paper!

I still think cheap coins (0.10 or 0.25) with a simple protection (gold scratch-off) would be best.

I believe an intact hologram will keep water off the paper for quite a long time.

They do make waterproof adhesive lables that can be run through an inkjet(i do need to get that up in my thread) if waterprofing is desireable. Did you give the coins a test in your laser yet?

Not quite true; they just have to be in the blockchain.

http://firstbits.com/1ecdsa

But sending an address 0 coins is at least as hard as sending it any other value…

I'd probably buy 24 if they were reasonably priced and I could get them before Hanukkah. 8 days, 3 kids... plus they could play dreidel with bitcoins. Awesome!

OK, here is a random thought...

What if I sold rolls of 50 of the bitcoin brass coins?  The exact same 1 BTC coin, but just the metal part.  I could offer this today.

I have like 6,000 of ones with year 2011 left, and have already ordered some with the year 2012 printed on them.

A roll of 50 1BTC blanks, I could sell for as little as 10BTC.

0.2 BTC / coin isn't too bad a price.  I probably couldn't buy 50 of them though.  But it does sound like a good idea...

So that would basically be 50 blanks like the "Broken 1 BTC" that you currently sell?

They are just clean blanks. "broken coins" come with a ruined sticker, the roll of 50 would just be clean coins with no sticker.

Me personally, not interested. Unless I misunderstood, it would be no different than buying tokens for a carwash and giving them to people saying they are bitcoins.

Same here. Tokens without actual bitcoin value is worthless to me. Stick with the 0.1 btc aluminum coins. I will definitely buy them to give away and help promote bitcoins.

Yes, I think part of the allure is that they contain actual bitcoin value that you can use.

I suppose you're right.

What if I offered a roll of 50 blanks, plus 50 printed gold foil stickers with the bitcoin addresses on them.  I preload, or you preload, but either way, you stick them on.  I actually have gold foil round stickers (same size as holograms) that have an invisible layer that can be printed on.  If I don't have to apply the stickers by hand, the price goes way down.

All of these are materials I have today, right now.  Minting new coins, that'll be a couple months.

I assume these would be 1 btc since the coins say 1 btc on them, right? Are you thinking of printing the mini key right on the gold foil?

I'm just wondering if this will cause confusion with your original 1 btc series since the coin will look the same.

If you want a less labour intensive way to create physical bitcoins, has anyone looked in to smartcards and/or NFC? Granted, not all that many PCs have smartcard readers, but its becoming more and more popular, at least here for homebanking and to read our digital ID cards for stuff like online taxes and any other government communications. NFC is also poised to become a standard feature on smartphones if nothing else.

Not sure what it would cost, or how you would go about implementing a bitcoin wallet on it properly, but it kind a makes sense for a digital currency. It may not have the charm of the coins, but unlike the coins, they could become quite useful.

I would have no problem applying some stickers.  But if the end user applies the stickers and/or loads the bitcoin value, then there would be no guarantee that the only copy of the private key is the copy on the coin.  In other words, the BTC value of the coin becomes very suspect in terms of using one as actual payment. But I suppose that would be ok, given that these would mostly be used for promotional purposes.  Also, are we talking about re-purposing the 1BTC blanks for this or the new aluminum coins?

No one ought to accept one as payment.  In fact, I could make it very clear, printing "single use only" on the sticker.  Remember, anybody with a peeled Casascius coin could already do this themselves, attempting to pass the token off on somebody who doesn't realize that the value of a bitcoin is in its key and the blockchain, not the piece of metal itself.  It's for that reason I deliberately avoided marking the piece of metal as a brand name.  It's an anonymous piece of metal that says "1 Bitcoin", backed by nobody.

The fact that the private key could be copied, in such a case, is actually desirable: you can spam these coins out IRL, (geocaching, etc.), and at some later date, take back the BTC from the ones that never got used.  The recipient never paid for them, so it's not like they should be concerned that they got nothing for nothing.  If they wanted the value, they should have redeemed them in a timely manner.  I get checks in the mail all the time (mail-in rebates, or refund for paying too much co-pay at the doctor, for example), that expire if I don't cash them in 90 days.  If I don't deposit them in time, it's my loss.  I could print "must redeem by 3/31/2012" on the stickers as well.

The logistics would be the same whether it's repurposing 1BTC blanks versus doing new aluminum coins.  The aluminum coins would be a bit cheaper, but I happen to have a surplus of the regular coins, assuming I decide that in 2012, I want to issue as few "2011" coins as possible.  And I have them right now.  I could go print off a stack of gold foil sticker sheets with private keys and start taking orders this weekend.  And thanks to USPS Flat Rate Priority Mail Box, I can ship a good 500+ coins anywhere in the USA for $4.75 (or worldwide up to 250 coins for $13.25).

+1  Perhaps include a code with the coin that allows the bearer to purchase a replacement coin with the same key.

I'd love a roll.

This has got me thinking about all kinds of things, such as embedding a metal strip with the private key inside the coin, and you could break a seal to pull it out.  Or micro RFID chips (that can only be read from millimeters away) embedded inside.  I don't know if/how RFID would work with a metallic coin though. Nothing very practical though....

Again, what can you use 0.1BTC for?  Does any vendor sell anything for so little?  Can you withdraw such a small amount?

You can hold it like a penny stock.

I agree, it's not much use.  But it's a heck of a lot more intriguing than being worth nothing.

It was worth as much as $3.20 earlier this year. :)