I have the bed off of my truck right now to so I can build some brackets to mount my air tanks under the truck so I can get them out of the bed. While the bed is off, I was wondering if there is any maintenance that can be done on the valves. The truck has been 'bagged for over 3 years now, and I've never taken the valves apart. Is there any type of oil or anything I should drop inside to keep the internals in good shape?