I did not see anyone here mention receipt paper, because I have had several receipts' ink fade away to nothing in less than 2 years. I dunno what ink is used, but the paper is pretty thin.
How many coins do you have with receipt paper that was used in them?
thanks!
Yeah.....
Pretty sure it was mentioned above, but receipt paper and the paper that is used by printers like the Piper Paper Wallet printer are different.
Yes, most retail receipts will fade quickly... more so, they really do not think you will keep them.
I always make a photocopy and save with original... not perfect but at least a copy for proof if needed more than 2-3 yrs down the road.
Most retail receipt are printed on thermal paper, the printer is an array of small heat emitters which the paper pass through, when thermal paper is subjected to heat then will it turn black. It is a commonly known that the print will not last much more than a year. Perfect for retail as it is cheap and reliable, and any warranty proff would be more or less gone after a year. Totally nogo for private keys.