After literally 20 years of using alcohol based cleaning products (and occasionally canned Freon) to clean dirty/oxidized cartridge contacts on everything from Atari to N64 games, I recently came across something at my job that made me curious enough to experiment with ...

Stainless Steel Polish w/ surface preservative.

Now, I've never been an advocate of using anything that "strips" soft metals to clean cartridge contacts (unless the oxidation has gotten to the green-mold level) ... but since this product was designed to remove impurities like oxidation as well as polish and seal, I figured what harm could it do to one of my 50 doubles of Combat or Super Mario/Duck Hunt.

After applying a small amount to an NES cleaning pad, I was happy to find that it not only removed all the crap (dust & dirt) from the cartridge, but also restored the copper contacts to a level of shine that they probably hadn't seen since manufacture.

In actuality, I didn't test it on Combat or Super Mario/Duck Hunt - I tested it on two of the FILTHIEST games that were in my collection and within arms reach - a copy of California Games for the 2600, and a copy of Monopoly for the NES. After using the product on both, they both worked on first insert. No retires needed, and prior to cleaning, both were in piss poor shape contact-wise.

Now, I'm not a chemist. So I can't really say what kind of long term effect this could have on the contacts, but I would assume that anything with "polish" compound in it will only ever "build up" over time, and not "strip" or "corrode" cartridges to any worse condition than they already are.

And my initial results are at LEAST enough to prove that it may be worth having a can of the stuff around to "resurrect" games that the bottle of alcohol simply won't work on.

The SPECIFIC brand of cleaner I picked up is called "Sheila Shine"

http://www.sheilashineinc.com/

Again, I don't claim to be a chemist ... so if you are and you see something in the contents that could potentially be dangerous to circuitry or plastics, feel free to let us know...otherwise, save the rubbing alcohol for scrapes and bruises and give the polish a try!