Some materials, such as concrete, soft woods, stone, specially treated metals, plastics, or other man-made materials, might have unpredictable surface characteristics. Therefore, we recommend that you test for adhesion by applying the caulk/sealant to a small area before proceeding with an entire job. It is also very important to prepare surfaces properly. Surface preparation should be done on the same day you apply the product. The following are guidelines for preparing a variety of surfaces. Concrete, masonry, and stone: Use a wire brush to remove the old caulk/sealant, dirt, dust, and loose particles. All contaminants and impurities must be cleaned off, such as concrete form release agents, water repellents, and other surface treatments and protective coatings. Porous surfaces: Use sandpaper or a wire brush where necessary to provide a sound, clean surface. Metal, glass, and plastic: Clean the surface with a solvent such as mineral spirits or a lacquer thinner. When using solvents, always wipe the surface dry with a clean cloth or lintless paper towels. Never allow a solvent to air dry or evaporate without wiping. Caution: Only use these solvents in a well-ventilated area and follow all safety precautions and instructions listed on the product label. When solvents are used, proper safety precautions must be observed. General: Do not use silicone sealant on any galvanized surface. Do not use below the water level. Cleaning surfaces with detergent or soap and water is not recommended as silicone will not adhere to surfaces with any soap scum/residue present.