I have seen some sick systems and games in my travels. It is a scary thing to see how some people treat stuff. Cigarette smoke is by far the most disgusting. If you clean with a white towel the brown scum will cover it after only a few swipes. I must admit that I do enjoy taking them apart and cleaning them from top to bottom. I just worked on an original gameboy the other day that was filthy. After a good soaking in the sink with some bleach the case looks almost new, now I am just waiting for a new screen to arrive and it will be good to go.