A schoolfellow named Richard sussed how to cheat the dryers. You could bend a paperclip to the shape of a dime, and because they were identical width, your paperclip would fill the vertical coin slot perfectly as you pushed in the slider. You'd hold the straight end of the paperclip to prevent it dropping down the box, and simply remove it when done.
The same fellow figured how to steal sodas from the lobby machine. Cans were held in place by aluminum fingers on either side of their chutes; just reach up and retract the fingers with yours, a can falls into your palm.
I later learned he was from a wealthy family in New England. His monthly pocket allowance would have paid my mother's rent.