I have a Scag Tiger Cub and it shows dirt and grime terribly. What is the best chemical used to take that stuff off. I use a 2400 lb pressure washer and still have to scrub like crazy to clean the mower. My front rims look black instead of orange and a brush will not get into the smaller hard to reach places. What chemical or chemicals do you or mower shops use to remove the stuff and where can I get some. Thanks.