Actually, there is this chemical compound, not a hazard to humans, well if you swallow it I am sure there would be concequences. But it has no damaging effects on electronics once so ever.
It is very expensive, but you can submerge your entire PC in it and control whatever the temperature is.
Before Tech TV sucked, they showed it on Screen Savers. They submerged a web cam in a tank of it and it works perfectly.