mewithoutYou52 wrote on 22. Dec 2006 at 00:13:
If alcohol works so well, why does the back of every cartridge say not to use alcohol? Not saying you're wrong, just a general question.
Most likely for liability reasons. Nintendo games were targeted at kids ages 6-15. Kids that young should only be using any sort of alcohol with supervision, like in a chemistry classroom, or with their parent's help to dress a wound.
My dad used to have a jug of pure ethanol for cleaning contacts in the field, he used to work in radio comm in the army. Won't chemically do a thing to copper. Cooktop cleaners are a good alternative because many of them include alcohol as their suspension medium, and also include detergents. The advantage is it smells a lot better than the purer forms of alcohol, and the detergent cleans up the dust in the cart like a cinch. At Dain's recommendation, I use Weiman's Cooktop Cleaner because it's easy to find (Wal-Mart cleaning aisle). But anything with alcohol and detergent is fine.
Over long-term use oxidation will happen between any electronic connection that's not soldered/airtight. Thing is, NES carts don't stay in the unit long-term, and if they do they're in storage and not plugged in the whole time. The kind of oxidation you may have read about in numerous FAQ's simply doesn't have time to set in on an NES cart. Probably 99% of the crud on a cart's connection is dust, dirt so the surfactants in detergent literally pull the filth off and it redeposits on your q-tip. I've had relatively clean-looking carts produce q-tips that look like they were dipped in motor oil after using Weiman's.
Pinball machines, arcade machines where the chip/rom is soft-plugged into the board, or the boards are plugged into one another will develop true oxidation over time as they're left on for days, months, years on end. Then you can use the scotch-brite, or pencil erasers, or whatever. Otherwise, q-tips require a lot less elbow grease, are cheaper and more disposable.