I think that it is a bit niave of everyone to think that a drug dealer would use a wall and a pill bottle to collect payment. They collect upon purchase, credit lines don't really apply until people start buying huge shipments of drugs. The money could be the result of some petty theft, otherwise it would stay in someones pocket or in the bank. I say use the money to make some insanley difficult multicache, with a few valuable items inside, and hide it at the top of a mountain or in the middle of a swamp and let the cachers have at it.