Just had my boat lifted out of the lake for service etc, whilst out it was the ideal time to give her a good machine polish and wax. I have found a product which works brilliant to give the surface a good clean before polishing. Its called Muc off and is designed for caravans and motorhomes. Just spray it on and wipe it off, or for the really difficult places like hatch covers using a soft hand brush works well. I only found the stuff because we have a caravan as well so thought i would give it a go on the boat...it saved hours!