Nicotine stains were so bad on some of my SFC games that they were sticky. One particular copy of Bishoujo Senshi Sailor Moon was so bad it ended up in the trash.
That has to be one of the funniest things I've ever read on these forums, no offense intended. Pull up a couple videos of some pachinko parlors.
Aside from tobacco related problems, I haven't had many other issues to be honest.