https://www.dickinson.edu/news/article/3193/dickinson_college_chemistry_class_explores_the_presence_of_drug_residue_on_us_currency

Here’s a startling fact: Roughly 90 percent of the dollar bills in circulation in the U.S. have been shown to contain cocaine residue.

So they just steal 90% of the moneys for no reason, cool cool.

edit No wait i was stupid, they just sniff for cash, not drugs, and just keep 100%