The good thing about EM pins is they still make everything you need to get them going and the parts are reality cheap. So once you get all the contacts clean and repair all the rodent chewed up wires (base on where it came from) and the machine all working, the best thing for it is to play it.....most contacts are self cleaning.
Here's a link to a great EM repair guide that I reference quite offer.
http://www.pinrepair.com/em/index.htmJim (Kilroy) is right it's wise to get a manual and schematic for your pin. trust me the come in handy!
Good Luck!