While Rob has been compounding the trailer with Nuvite "C", I have been using "C" and a 6" wheel on an electric drill to polish the door & window jambs. I'm also using my Foredom (similar to a Dremmel tool) to get into the tiny places that the larger tools can't. Works like a charm!
I've heard the same about steel or stainless steel wool, for that matter ANY dissimilar metal on aluminum. Eventually, it'll cause rust or corrosion. For some of the really tough scratched areas that need "extra work" we have been using the plastic Scotch Brite pads that come in different grades and can be found at an automotive painter's supply store. We only use the fine & extra fine grades, before compounding. Works well...