I have just completed cleaning a mocha 401A and it turned out looking like new. The first step is to wipe the heavy dirt off with Dawn dish soap using a damp cloth. Then the rest of the dirt was cleaned off with Meguiar's #10 mirror glaze clear plastic polish and cotton balls. (Use #10 only do not substitute.) This cleaning takes a long time and a lot of rubbing. Finish off with a coat of Meguiar's Deep Crystal Carnauba Wax and give a second coat in a couple of days.