Oil cool the computers. I don't have the link but a google search will show you a lot of interesting builds. You don't have to worry about dust or filters because te entire pc is submerged in oil.
Well then you get other problems such as dirty oil (unless you have a good seal). The biggest problem I see is that it lasts as long as the shortest lifespan of all the components then you get to go through buying a new one or the mess of replacing that part.