Fiberglass Surface Prep, YMA601 is the first step in a 2step system for removing mold release agents from gelcoat prior to application of antifouling paint. Pigmented formula acts as a guide during the cleaning process. Applies easily with Scotch-Brite pad. Rinse with fresh water or wipe clean to remove. Abrasive properties of the Fiberglass Surface Prep thoroughly clean the gelcoat and provides key for Fiberglass No Sand Primer.