I have recently purchased a boat with an after market custom Aluminum T-Top. I have tried to clean it with a bunch of different brands of cleaners but none have taken off the buildup. I am uncertain wether or not it is anodized but there is no rust, just a lot of small black/grey bumps of something. The cleaners I have used thus far are all OK for anodized products and I don't want to use anything like sandpaper or wool in case it is anodized. The buildup of blackish/grey gunk and simply won't come off. I have asked the pros how to tell if it is anodized and the answers I have received seem to say if it is shiny it is anodized. well it wasn't shiny at first but after polishing it is so I still can't tell. The fact remains that nothing seems to get the buildup/residue off. Any hints, tips or suggestions on what I can do to get rid of all of these samll spots of gunk and how to determine wether it is galvanized or not.