When I was in my early teens my friends and I would “rack-up” a bunch of free games on pinball and other machines by taping a length of thread to a quarter and slowly dropping it into the coin slot and gently moving it up and down.
Anyone else do this?
Sure, but later coin acceptors were much better at preventing this.
The only thing I ever robbed like that was the Magic Fingers motel bed vibrator. A dime in a 6 inch long piece of cellophane tape worked fine.