I'm following this thread closely... I have to do the exact same sort of touchup on a game of mine. Problem I have is that I don't have the awesome vectorized scan you have and am going to have to do that part myself.

Are those sanded off metal parts just going to corrode again fairly quickly? That's what always happens when I sand off exposed metal and leave it bare.

That's what I'm thinking. What are they originally coated with? Obviously that sort of corrosion takes either years or a beach type environment. They have to be coated with something from the factory.

I suppose if you were to stuff a paper towel in there and spray everything else it might work. Only the spring needs to move. The rest may as well be an insulated connection. By the time you sand it and do that, though, you're bordering on a level of effort that might just make more sense to replace all of the sockets.

Especially given that these are Bally sockets and are probably going to be wonky no matter what.