When I was in the Marine Corps reserve we would turn the weapons back in at the end of drill weekend and the next month when we would check them out they would be covered in surface rust. I knew for a fact that they were being turned in clean and with a light coat of oil since I was one of the inspecting S/NCO's. Seems the armorer was spraying them down with WD 40 and once he stopped the problem was solved. IMHO, it's good for practically nothing.
As far as graphite goes it came from a locksmith in 65 that made new keys for the trunk latch for my 36 that I had found in a junkyard.