I just resurrected a 20+ year old MXR graphic EQ from my basement, and want to start using it. A couple of the sliders didn't work until I exercised them for a while. I don't want the EQ to be iffy on a gig. Is there a spray, preferably from Radio Shack, that is preferred for cleaning these pots? Yeah, I know, buy a new one. But the MXR is a perfectly good design, and was never heavily used before my brother gave it to me.