You know the trick. When the game wouldn't load properly, you would take it out, blow in the open end to dislodge dust, grit, peanut butter or what-have-you from the electrical contacts, then put it back in and hope that it worked (or repeated as necessary).
I personally used the T-shirt variation whereby you stretch the front of your shirt over the open end of the cartridge, then blow through it — the shirt captures the dust and prevents you from spitting into the game as you blow.
Thing is, I still do it. Like, regularly. Any time my gadgets act up — boom, I've got the battery out and am blowing like a hurricane into my electronics. Anybody else still do this too?