I had free laundry for most of my freshman year of college. We had coin operated machines, and somebody quickly figured out that you can strip 2 wires and just touch them together, or touch a coin to both of them, and every time you did that the machine would think a coin had been inserted. Eventually the college caught on and one day I went down there and all the machines were taken apart with maintenance guys working on them, and after that there was a heavy duty housing for the coin acceptor with no exposed wires. It was nice while it lasted!