A little old lady is walking down the street, dragging two plastic bin bags, one in each hand.  There's a hole in one of the bags and once in a while a £20 note flies out of it onto the pavement.

Noticing this, a policeman stops her.  "Madam, there are £20 notes falling out of that bag..."

"Damn!" says the little old lady...."I'd better go back and see if I can find some of them.  Thanks for the warning!"

"Well, now, not so fast," says the policeman. "How did you get all that money?  Did you steal it?"

"Oh, no", says the little old lady. "You see, my back garden backs onto the car park of the football stadium.  Each time there's a game, a lot of fans come and pee in the bushes, right into my flower beds!" So, I go and stand behind the bushes with a big hedge clipper, and each time someone sticks his thingie through the bushes, I grab it and I say: '£20 or off it comes!' "

"Hey, not a bad idea!" laughs the cop. "Good luck!" By the way, what's in the other bag?"

"Well", says the little old lady, "Not all of them pay."