Before tearing the unit apart, I would suggest you simply spray the switch with a good contact cleaner/lube... Specifically Caig DeOxIt D5. (Don't use that alcohol based crap from Radio Shack, Walgeens, etc.)
Just yesterday I had another D5 miracle: the power supply and output switch for my Line 6 Variax started making ugly, bad connection noise. I opened it, sprayed the switches and jacks, and the unit returned to blessed silence. It's an electronic repair kit in a can.