Go to your local hobby shop and buy a bottle of "RC Shock Oil", is what all the cool peeps use, and buy your keyboard duster from computer stores, check the label (generally in the WARNING/FIRST AID part of the label) to see if it's diflouroethane (weaker) or tetraflouroethane (stronger, weaker than propane).
Originally Posted by The Saint
I've seen hopup sleeve swelling from even the silicon oil from AI. I think depends on the rubber used.
AI stuff is 5 weight, stuff I always use is 20-30 weight, since I also use it for GBB internals.