Blowing into cartridges. The practice has basically been around as long as video games have existed — almost like a magic formula. Cartridge isn’t working? Blow into it, and it’ll work again. But does it actually help?
Looking around on the internet, it’s pretty clear the answer here is “no.” Nintendo even starting printing increasingly specific advice on the backs of its cartridges. On the SNES, it said to only use a proper cleaning kit. On the N64, it stated outright on each game: “DO NOT BLOW ON THE EDGE CONNECTOR.”
The practice goes back to the original NES, which used to have issues with the pins not lining up between the cartridge and the system when inserted. Removing the game and reinserting it would give the cartridge another chance to line up correctly. That part of fixing the problem got confused with blowing on it, and the myth was born.
The blowing itself? It can actually make things worse, since you’re basically spitting on sensitive electronic contacts. So, yeah, don’t blow into your cartridges. Even if you’re really frustrated with your NES.