You can use a rack cleaner such as Rack Attack by Trebla and there are others on the market as well. You can also use Lysol toilet bowl cleaner but only use in a well ventilated area and rinse thoroughly with lot's of fresh water. If the gears and other parts are just stained that's normal and there is not much you can do about it, they will not remain bright red as when new and the staining is of no consequence except for being cosmetic. Build up is another issue altogether and must be cleaned off.