I just cleaned mine at work. I took the primary and secondary totally apart.......all but the spider. They were filthy with brownish red dust everywhere. I put them in the parts washer in our machine shop and lighty scrubbed everything with a soft brush. Then used compressed air to dry with some clean cloths. I'll let them sit for a few days to make sure all is dry. My machinist buddy checked all the bushings,rollers ,pins, pin bushings and tower guides for wear. I cleaned up all the little washers, helix buttons, etc. with emery cloth to rid any burrs. Polished and buffed helix ramp angles for a smooth sliding surface. Lightly emery clothed clutch faces for better belt grip and put a very slight amount of a special pure synthetic machine lube on pin guides etc.......stuff doesn't break down. Not really recommended by Yamaha, but the stuff we get is for special purpose machinery (expensive) and really makes the clutches more responsive as long as you don't over do it.