I have a few year old travel trailer with painted aluminum siding (the ribbed type) that is oxidized and stained. I just bought a PC and some pads and was thinking cleaning up my rv would be a good way to get familiar with the PC. I dont have a whole lot of products available to me locally and would like to get this done before the weekend- so no time to order online. I purchased some Meguiars 67 locally to try and take off the staining and oxidation and started a section this afternoon. I started with a white pad and the machine set on 4, and it didn't do much. I turned the machine all the way up and still didn't do much so I tried an orange pad. With the machine on 3 it works pretty good, but I made a thin spot on the paint so I stopped and went back to the white pad. Am I on the right track here? Do I continue with the white pad and make multiple passes?