Best thing to do is never let them dry, as soon as the boat hits the trailer, wipe it down with a rag and some water, wax it 2-3 times a year and use the bow-to-stern or BBS once you get home. If that stuff dries on there it is a real pain to get off, and will begin to yellow the boat (if white). Ive fished coastal areas for years and have never had any issues with scum lines becoming hard to remove by do it this way. For now though good ole elbow grease, I would use a buffing compund first, either by hand or by buffer at low speed, then a good coat of wax.
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