I read somewhere that all currency is drug-contaminated
Some years ago, back in the mid 1990's IIRC, the Treasury Department released a report that said 80% of all $20's, $50's and $100's in circulation had cocaine residue on them. There were quite a few less than honest police departments around the country that used this tactic to seize large amounts of cash in traffic stops. Two that I remember who were doing this were Volusia County in Florida and St. Martin's Parish in Louisiana. Not saying that this is the situation here, but it has been known to happen.