Admiral,
Try this product from Mother's: Original Formula Carnauba Cleaner Wax. I've used it on the cladding on my red/gray Ty many times. It had all kinds of blotches, water marks/stains, etc.. and the cleaner wax took care of it all. Get the paste in the tin can, it seems to work better than the stuff in the bottle.
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Original Formula Carnauba Cleaner Wax is designed to be the one-step plan for paint preservation. This special Carnauba Cleaner Wax is formulated to clean and protect in just one application. We used the same Brazilian #1 yellow carnauba that makes our Pure Carnauba Wax so special, and combined it with a light polish that will smooth minor flaws and make your paint snap. Carnauba Cleaner Wax is especially effective on fiberglass and gel coats. Available in long-lasting, easy-to-apply liquid or paste.[/font]