I was tracking down a short circut in a wiring harness that had been submerged in water for a bit of a long time. When I found the issue at a connection and opened it up, water poured out. When I was cleaning the connection, I grabbed my WD 40 can and gave both sides of the connection a good shot. The young Soldier I was teaching said "I thought that stuff was only for cleaning guns?" By the time I had everything fixed he knew a lot more about WD 40 than he ever might have liked to know. I use 3 in 1 oil lately for lube, but Ive used motor oil, turbine engine oil, rem oil and whatever the military had available at the time while I as serving.