I always found that if blowing no longer worked, that I could plug it into the Game Genie loader and it would usually work. I suspect because the fit into the Genie was much tighter and the pins were less worn or corroded.
Definitely. Around my old neighborhood, Game Genie was a highly prized accessory if only for that reason. Cheating was all well and good, but having your Nintendo actually work? That was the real advantage!