Is the game working ? Don't.

Don't. Unless you want to replace every pin and connector.

LTG : )

If it's not broke,don't try and fix it. Doing so could open up a can of worms and I have made that noob mistake,never again.
-Mike

Remember the opposite or good is better!

You sand or aggressively clean them, you risk removing the plating on them. Then you'll be dealing with them forever after, or until you replace them all.

LTG : )

As a noob once myself,I found with my TAFG,don't fix anything till its not working!! In the beginning,I cost myself time and money,fiddling with stuff I thought i could do!!Be careful!!Have fun!!

Like LTG stated be careful otherwise you end up replacing the headers on each board and then connector on the wires itself not something for a noob or faint of heart to attempt even guys like myself who have done this many times do it only because we have to at some point. It's not exactly fun and you can make things worse if not careful from damage to the boards or mess up the wiring harness. Yes i'm one of those pinheads who probably spends more time fixing then playing but this is how i grow the collection a project box here and there.
After many night's, weekends some more money then planed on you end up with a working game. The more time /effort and money you throw at it the better it comes out. Something in time you and others may decide to do having pinside as a source of great knowledge in doing project like this or lead you to the people /companies who will do it.

Not sure it's necessary given it's been repeated three times (at least)... but the absolute first rule of pinball is that you never, ever under any circumstance, fix something that's not broken. Seems stupid, gee why the heck would anyone fix something that's working??? Because pinball machines are amazing mechanical contraptions with more bells, whistles, lights, wires, switches, and cool looking whiz than any sane person could avoid messing with. Just STOP, and don't do it.

The second rule of pinball (even harder to follow than the first) is that you never fix anything until you know what's broken. That means that if the flippers stop working, before you go ripping into the big obvious flipper mechanism, or the obvious flipper button, or the less obvious wire leading from them to a computer or switch relay, leading to the even less obvious and nearly invisible micro electronic component or other complicated part, all of which actually must work together and any one of which might be broken and causing the problem (or more likely, working and broken by messing with it).... don't try to fix a problem until you know what the problem is.

This is a long way around saying that when stuff stops working, if you want to fix it- STOP, unplug the game, post exactly what you did prior to the event, fully describe what you think is broken and WHY you think that's broken and then wait until someone asks a question or gives a suggestion. Then, carefully proceed and ask as many questions as you need to be sure your doing the right thing (let us know your new at this and have zero electronics experience, or if your a PhD electrical engineer who designs chips for a living but has a new pinball habit). This is how you will fix your game and learn how to do so independently. You will still probably break stuff, everyone does and a little knowledge is a dangerous thing... but if your patient and ask questions and DO what people suggest, you will usually end up with a working game pretty fast and usually won't break anything expensive doing it. Hard problems exist, ghosts do not, so anything is fixable if your willing to work at it and learn.

Finally, be sure to have fun. For some that means digging in, getting dirty, amd fixing their own games, for others it's modding games and making them look cool and personal, others collect like the very best hoarders and always are on the look out for the next game, and many just want a functioning game and are more than happy to pay to have it fixed... your in there somewhere, just be sure to keep it fun. Don't do stuff you don't want to unless you absolutely have to or it stops being fun.