UGH! I've been collecting games practically my whole life, and one thing that REALLY gets me is when people deface a game. Stickers, fingernail polish, markers, whatever they can do to make it U.G.L.Y. Over the years I have figured out ways to make them look new again. I am going to share with you some of the things I do to bring them back into their "original" state as best as possible. Sort of a "cart tune-up" if you will.
First and foremost, if a game doesn't work, then what's the point. First thing I do to EVERY cart, is take it apart, and clean the pins off as best as possible. What *I* do (and everyone has different takes on this), is dab a small amount of tooth paste on the pins, and THOROUGHLY rub the contacts with my fingers. You will notice that the paste eventually starts to turn, grey - black.. this is good. After a good rub down, I wet a tooth brush and gently brush the residue off until most of it is gone, while keeping any water away from the IC chips of course. Once all the tooth paste is off, I take a cotton cloth and polish the pins clean. I have SAVED many a game by doing this (especially NES games). If after this it still looks bad, repeat until it looks good.
Next, the stickers. Oh God, the stickers. Some stickers you can be very lucky and peel them right off (if they have not been on there too long), if it seems like it's not gonna happen, STOP. Pull out the hair dryer, and warm up the sticker, slowly peel it back while you continue to blow hot air on it. This has worked for me SEVERAL times, and is highly recommended! If done properly it should even take the sticker residue off with the sticker. If not:
The residue, holy hell - the residue! If the sticker was successfully removed without a gob of residue left behind, usually there will be an outline where the sticker WAS. You'll have to remove that. Sometimes the sticker just leaves residue EVERYWHERE. DO NOT leave it on the cart, it will accumulate dust, debris, whatever can attach itself to it, and will look like ASS in no time. The trick? Goof-Off. Apply a small amount to a cotton cloth and rub until it's gone. Not everyone has Goof-Off, so if you don't you can take a VERY HOT WET RAG and use a bit of elbow grease. The HOT water will eventually cut through it. Sometimes, you will find stickers that have metal strips in them, those can be a royal PITA. I've found, that usually if you heat them up with a hair dryer (much longer than just the sticker), EVENTUALLY you'll be able to peel it off.
Finally, once all the stickers/residue has been removed from the cart, take your hot rag and give it all a final wipe-down. I have found that wiping the label down does not cause any problems as long as the rag is not sopping wet. After you've wiped it down, polish off the cart with a cotton towel.
Finally, re-assemble the cartridge. Now you have a clean, sticker free, clean pinned cartridge ready for the next person to put stickers on it.
Problem UNSOLVED. Permanent marker. I have over the years tried to figure out a way to remove it, without destroying the texture/surface of the cart. Usually, if it has marker, I leave it. Because I don't know what to do about that.
Does ANYONE have a way to remove permanent marker???
NOTE: This is just how *I* do things, you may do things a different way. Please share with us in defeating this plague.