You can get contact cleaner. I wouldn't use WD-40. May too much oil. Contact cleaner spray is highly volatile and won't leave a residue to gum up the pot like oil will.
static when adjusting gain control
I have an Audible Illusions L-1 pre amp which produces a sound which I can only describe as STATIC. The static only occurs when I adjust the left chanell gain control and only comes from the left speaker. There is no static once the control is set. There is no such static from the right side control nor is there any from the master volume control. Can this problem be corrected easily? Does it pose a problem if not fixed? Thanks for any advice. John