"Tradin'" in the Secret Admirer

[Rich3]

I always liked the episode where Bobby creates an imaginary secret admirer for Cindy, then gets one of her classmates to pretend to be the admirer. I liked the scene where Bobby asks him, "Do you want to do some tradin'?"

Then they sit down and empty their pockets. They had all sorts of cool little toys and things.

It was probably in Tom Sawyer, but I've never seen that portrayed in TV or movies much. I know when I was a kid I used to carry things like: old keys, rabbit's foot, dice, pocket knives, keychains, unusual coins, etc.