I can't polish my CCD, but I have polished many an aluminum wheel on my now sold 40' Monaco Dynasty MoHo. I found a great polishing combo from.......ALCOA of all people. You would think if they make the aluminum, they should know how to polish it!
You don't have to use their polishing compounds, but they do make a final finish that is a clearcoat of sorts but not in the true sense. It doesn't provide a plastic-like top layer, but chemically bonds in with the aluminum to retard tarnish and oxydation. It comes right off with the next round of polishing too. It made the polish on the MoHo wheels last about 6 months. Check the Alcoa web site for more info.