Yeah, I used to clean my NES/Genesis games by taking them apart to clean the contacts too but it is a lot of work. Nowadays I just use 90% rubbing alcohol and eyeball the contacts to make sure they don't look too gunky. If it looks real bad I'll crack it apart but try to avoid it if I can.
It's a ridiculous amount of work cleaning those pins. I've been backlogged on cleaning, so I constantly have a stack of SNES/NES games that aren't with the rest because I haven't cleaned them yet. That's good you do that though, especially with NES games. Prolonging getting your machine dirty, and not having to boil down the 72 connector so frequently. And besides, I don't think anyone likes that hot plastic small.
It reminds me of leukaemia and respiratory cancer