The popular myth has been debunked: you can't blow on cartridges to make them work. Actually, blowing on the cartridge might damage it. Sorry, folks. It's true.
But, apparently the myth never needed to be debunked in the first place. Nintendo has kind of been telling us all along. We just weren't paying attention. Luke Plunkett wrote about this before, but here's photographic evidence.
Ah, the hours we could have all saved if we bothered to read, eh?