Spray 100% on spiders under all overhangs outside of boat. Spray 50% in showers when done, will keep shower fresh and mildew from forming. Great for deordoring & kills mold & mildew. Also will get rid of all odors if keep in plastic or glass bowls overnight. Vinegar is the most used cleaning product on all my Nordic Tugs. If you have a very very bad mold & mildew situation you can use Tilex to clean it up. But use caution.