thank you 
ops;
in 1993, the US courts rejected the use of money that had traces of
cocaine on it as evidence in a drug case when it was found out in a
test that 95% of the randomly tested paper bills had traces of
cocaine on it..
the tainted money is in such wide circulation that the courts
decided that they could not depend on the fact that the money was
tainted with traces of cocaine to convict the owner of drug
possession..
a quick search turned up this reference: erowid.org
