Seriously though, I know you're not supposed to blow into cartridges because you can blow saliva in there, but whenever I need to get a cartridge to work, I just close my mouth like I'm about to whistle and blow lightly. I think it greatly reduces the amount of saliva released and it gets all the dust and dirt out just fine.
I also shake the cartridges. But there's no logical reason to do that, I just get lucky sometimes.
But hey, my Super Mario 64 went through the wash and it still works n___N.