Perhaps a better change would be to also have a cartridge that regularly gets a shot of canned air or something. That would isolate the "blowing" from the extra crap that could come out of someone's mouth.
The point of this is really that people who "blow" in their games UNAVOIDABLY get crap on the cartridge contacts, no matter what they do.
"And the book says: 'We may be through with the past, but the past ain't through with us.'"