The Effects of Smoking on Your Computer?

cencini asks: "Over the past few years, I've ended up fixing computers for a lot of different people, some of whom are smokers. One thing I've noticed about the smokers' computers (particularly those who smoke near their machine) is that they are absolutely disgusting inside. Is there anything that has linked smoking to computer damage (since we know the other types of damage it does), and has anybody else observed this phenomenon?" I too have looked into the insides of the boxen of heavy smokers, and I must confirm that it is not a pretty site. But aside from the asthetics (the yellowing plastic, the tar imbued dust, and that nasty residue) are there other, more subtle problems that can occur that can be connected to smoke damage?