Any gamer born in the 80s or earlier knows the routine all too well: if your Nintendo Entertainment System wasn't working, you pull out the game cartridge, blow into it, then try again until you achieve success. While many will defend the habit — citing the countless amount of times it worked — Mental_Floss set out to find the truth behind the myth by speaking with a number of individuals from the gaming industry and examining a real-world test of Nintendo's infamous 72-pin connector. Head to the source to get a brief history of the console and Nintendo's official cartridge care instructions, and prepare to have your childhood memories tarnished by the investigation's results.
Source:
http://www.theverge.com/2012/9/27/3419038/nintendo-entertainment-system-cartridge-blowing