I never let them build up grime. I spray it, scrub it, rinse it, every time I ride in the rain or every few rides if it's been dry. Simple green and the garden hose outside, dry in front of a fan inside, air blow water out of hidden areas, then rubbing alcohol the stubborn stuff, a pledge wipe down to shine it up, then lube the chain and all necessary items. Even the beater gets the same treatment.