Oh the memories!
We used to take drinking straws and take a mouthful of water (or Coke etc) and place the drink straw down the coin entrance. Once in place we would then blow the water down the straw slowly and keep doing that until the contact for the coin would be soaked. That would complete the circuit and we would then kick the door and it would add credits. So if a game like Bally's Star Trek it would pop 40 times until it maxed out on credits.
We would start to worry when this happened - especially when there was a pool of water under the front of the game from the water that was coming from the coin return
