I can't read the site, but this isn't something I worry about. Almost every banknote has cocaine traces on it, and given enough rotation most banknotes must have been in the hands of criminals. That's not a problem: money is fungible.
It's a problem if you're dealing with criminals. So don't do that

As soon as that "tainted" banknote enters the banking system, you're fucked. They will freeze the money and the police will interrogate you where you got it from.
What's wrong with catching murderers? The police won't come after you, but you may have information that can help them find the real bad guys. If you tell them you received the money when you sold cocaine, you have a problem. But if you got it for selling your car, I don't expect them to blame you.