Do you pee on your cup to clean it?

I think the subject says it all...after removing the cup in public restrooms if the cup is particularly messy then I'll pee on it to clean it off, then I might pat it dry with toilet paper before reinserting.(generally I just give it a rinse in the sink when I'm not in a restroom stall) I heard about this unusual cleaning technique first at a workshop from some longtime cup users. It might sound crazy at first, but I honestly recommend it. I haven't seen any mention of it here though - anyone else pee on their cup to clean it?