Chances are... there's cocaine in your wallet.
Researchers looked at 234 bank notes from the U.S. and found that 90 percent had small traces of the illegal drug.
Bills from larger cities, such as Baltimore, Boston and Detroit, were among those with the highest average cocaine levels. Salt Lake City had the lowest. Most of those analyzed from Washington had tiny amounts of cocaine.
Money can become contaminated with cocaine during drug deals, or when users snort the substance through rolled bills. It can then spread to other cash when banks process the money. Yuegang Zuo, a University of Massachusetts professor, led the study.