When it comes to keeping your Cyrstal Kayak clean, nothing does it better than the Crystal Kayak Mico-Fiber Cleaning & Water Bailing Sponge. As you use your kayak, water will begin to collect in the bottom of it. By using this sponge, you can clean it out without scratching your hull. Its recommended to use this sponge and fresh water to wipe does the hull of your kayak after each use.