On the front "corner" panels of our GlobeTrotter, they were VERY pitted from road debris being kicked up. There were little crater-like pits that had rough edges all over the surface. When we went to polish
it, every crater edge caught the fuzz & polish making a real mess so we did VERY LIGHTLY wet sand that panel with 1000 grit wet/dry. It worked out well and we did not go through the Alclad layer (or actually get rid of the pits themselves) - just took the edges off. I would only do this on a very damaged panel as a last resort prior to being prepared to replace the panel - NOT the entire trailer. For us, it worked out well on these two areas - but it is a pretty drastic approach to the entire trailer and easy to mess things up real bad.