Hmmm. Now I've always heard them referred to as "urinal mints".

I used to do an experiment at a bar I frequented. I'd lay some US cash in the bottom of the urinal and see how long it lasted. A $1 bill would sit there til doomsday, a 5$ bill would make it until 11:00, and a 10$ would be gone before my next whizz.

This hereby proves that cockroaches value currency much like humans...