I recently bought an NES, which I changed out the 72 pin connector Saturday. I only had like two games for it originally, then I struck gold at Goodwill and found a bunch of games for $2 each like Mario 2, Mario 3, Double Dragon, etc. I bought as many as I could afford and was disappointed when they weren't working correctly in my NES with the new pin connector. None of them worked, which seemed strange to me. I happen to have the correct gamebit for opening the cartridges laying around, so I opened Mario 2 up. The pins were covered in dirt and gunk that alcohol wouldn't even touch. I tried Brasso and Mario 2 works every time now. Mario 3 is fugged up, there's a piece of plastic missing inside the cart so if super glue doesn't work I'll have to find a donor cart due to the fact that the game board will not stay in place. Anyway, I'm starting to have regrets, a few of the games (Sesame Street and R.C. Pro AM) are loading with garbled graphics and I'm worried the brasso may have stripped some of the coating off the pins. I've used brasso with success for SNES games, but now the internet is telling me it's dangerous to use with NES games. How would you have cleaned them? Alcohol doesn't remove the dirt like brasso does, it takes about 5-6 qtips to get these games clean. I just find it strange that some of the games work perfectly while others just load with glitches graphics. Maybe the new pin connector is dirty from trying to load these dirty games? I just want to play some Mario 3. Who manages to bust the plastic inside the cart?