Not ask but try to see who seems to have lost it and then go ask if that person needs help. If he/she is the one, I'll give it back if not...go spend it. I mean, if million people are walking by, I'm not gonna give it to another clever who can say "oh yeah, it's mine!" Donate to charity? Only if it is right infront of me. I will just do that later, planned.
He lives under a club. By mistake, his taps deliver beer since the club was established. He asked the water company if he could pay as if it was water without re-establishing normality.
RE: what would you do if you saw a 100 dollar bill by the sidewalk?
What's your cause?