history: I was walking down the street and I found a 20$ bill! I was so happy I was walking down the street and I found a 20$ bill! I was so happy Did you try to find who the $20 belonged to?  It was just sitting in the grass_comma_ what am I supposed to do?
current: I would feel guilty keeping money that I did not earn or that was not mine. Maybe you could give the $20 to charity?
next: I need that money at the moment, plus I donate on the regular