I've been using a 1 gallon ultra quite Air compressor for the last 5 years, only 50psi max I keep the regulator at, I keep it indoors, so its less likely to built up moisture unlike my 36 gallon my garage. I only use that in extreme cases like my brothers neglected PC.
I got a few different size paint brushes, not the tiny walls or art work, but bigger ones for walls and trim, works good for dislodging stubborn dust that air wont get. But in extreme cases like smokers PC's, its gonna have to come apart regardless, air and brushes will still have a hard time getting that tar dust crap.