Does rubbing a coin on the vending machine make it always take a coin ?

[lemonsaresharp88]

basically at work there is a vending machine what sometimes doesn't take coins, so some people rub the coin on part of the vending machine just above the coin slot and beleive that makes it work. Is this even possible ?

[MoFayed]

You can't be sure of that. Inside a slot machine there is a thing called a 'coin comparator' (not sure about the spelling). It contains a coin of the type it is supposed to accept. If you put a coin in the machine various tests will be done to see if it balances what is already there, (weight, resistance etc.) if they match, the gate opens and the coin is accepted. If the contacts are dodgy or the coin they are comparing yours with is too old and worn (or even too new) then it may spit it out. You can alter the electrical resistance of a coin by warming it up, and improve contacts by spitting on it. Possibly.