I just finished a summer of boating with a trip on the Mississippi as far south as Hannibal, MO. I now find that the cowling and lower units on my outboards and the boat sides are covered with water spots and the motors look like they have some sort of scales on them. I tried a high pressure car wash and scrubbed for a few hours with Starbrite Cleaner Wax with little success. Does anyone have any suggestions?