I had not cleaned out my system since I got it in 2009. However, back in October I got Error 80010514, which basically meant my Bluray Laser couldn't read discs, and it turned out to be because my system was so dirty inside. So I had to bust it open and clean it out.
Can of compressed air, some cotton swabs, some rubbing alcohol, and some slight disassembly, and I had a clean system and a fixed error.
If you're not going to share with the entire class, then don't bother sharing at all.