Funny story: my wife thought I was a little crazy at first, but I sold a car recently and got paid several thousand dollars in cash. I tried my best to check the bills myself and tried to make sure I could track down the buyer if I needed to then signed over the title and gave him the keys. I decided to randomly pick 100’s out of the stack and spend them at local stores to make sure they were OK. Once I got through 5 or 6, I felt confident enough to deposit the rest into my bank account. I sort of felt like a criminal doing this but I just didn’t want to lose all that money if the bank confiscated it!