Reply by cabmaker

If I am using lac. which is usually what I spray I spray a bit of lac. thinner through then squirt oil (wd-40 or gun oil), which ever one I pickup first. I squirt into fluid side till it comes out the tip then squirt a bit into the air inlet. I also spray a bit into the cup as well. I do this even if I am using the gun the next day.

I mostly finish with a binks 2001 and have been doing it this way since I bought this gun in 1985. It has been overhauled twice now and has been used more than you could imagine ! Light oil is your friend for long life .