There are so many services that work as mixers, that are not designed specifically to be mixers.
go to:
https://exchange.bitparking.com/mainMake two accounts. Buy namecoin with one, send namecoin from one to the other through an external namecoin wallet. Do it with a delay (a few days) for best mixing. Then buy new BTC with the second account via the namecoin and send it as needed. If you trust them you can keep a small balance there as well. You pay less then a 2% fee overall.
Be sure to use reasonable mixing techniques, such as not using one large amount at once, and waiting time between transactions.
