[LAU] Pot rust

Hello all, Hardware related. For quite some time I had the volume knob fixed at one setting on the M-Audio Studiophile speakers, using the headphone jack connected to a pair of Sennheiser remote headphones with their own volume control (plus any software volume controls). Recently when I tried to use the M-Audio speakers w/o headphones I was surprised to find that the volume knob has what I call 'rust' as it makes a loud noisy sound when rotated. Is there any fix for this ? I kind of recall that there was some kind of spray that was sold at Radio Shacks way back then to remove the 'rust' off potentiometers. Anyone got the same problem ? Are the speakers casings to be opened to spray such stuff or can it find its way from the small spacing around the knob at the front ? And is this stuff still around anyways and does it work at all ? Cheers.