New currencies that are a natural for laundering

This post isn't about bitcoin, or about prison economies, although it's closer to the second then the first. Neal Becker points me to this article about the use of Tide detergent as a currency in which you can buy drugs...(the article is mostly about how Tide has become a target for professional shoplifters who can fence it without too much difficulty):

Suds for Drugs
Tide detergent: Works on tough stains. Can now also be traded for crack. A case study in American ingenuity, legal and otherwise.