I opened up a PC once to find it was 3/4 filled with fag ash. the owner was in the habit of tapping his ciggy on the front of the machine and the ash was drawn in by the fans. Unsurprisingly it was overheating as everything was inches deep in ash.
It was one of the more disgusting things I've ever dealt with working on PCs and it took a long time before the smell faded from memory.
Biting the hand that feeds IT
