Solid state games use low voltage current in the switch circuits. That is
why they require gold-plated contacts on the switches. Otherwise switch
closure will not be reliably detected. In a pinch you can substitute a clean
silver contact point for a damaged gold contact, but this will not work long
term. If you want it to work trouble-free for the long term you have to use
gold contact points. The problem with silver and other metals besides gold
is that they corrode. That is why gold is preferred--it does not corrode.