The process of firing white porcelain and ceramic tiles or other objects in a kiln under high temperatures makes the finish very hard and stain-resistant. Because of this, it is usually not necessary to seal the surface. Scratched or otherwise damaged porcelain and ceramic surfaces, however, can actually absorb stains. Because the stains seep into the material, they can be difficult to remove. When this happens, you can try some techniques to make your porcelain and ceramics white and shining again.
Blot spills that could stain with paper towels or use a wet-dry vacuum cleaner on white porcelain or ceramic tile floors immediately after the spill. Mop the tiles with clean water or a dilution of neutral-pH cleaner in water. Clean grout lines between tiles with a soft cotton cloth and warm water.
Soak white porcelain or ceramic objects in a solution of 40 per cent peroxide and distilled water to remove stains. Use the peroxide found at hair salon supply stores, not hydrogen peroxide found at chemists. Peroxide will burn your skin, so wear gloves to protect your hands. Submerge the object completely in the peroxide solution. If the item has a heavy coating of accumulated grease and dirt, soak it for several weeks or even months. Test a small area of the white porcelain or ceramic object before soaking to make sure the peroxide will not damage it. Rinse the object well in clean water. Use a little mild detergent in the water to remove the peroxide after soaking.
Wash the white porcelain or ceramic with a neutral-pH cleaner. This is especially good for tiled countertops and vanities. Consult the manufacturer of the tile for recommendations about what cleaner is best. Never use harsh chemicals, especially chlorine bleach, to clean porcelain or ceramics.
Be gentle with cleaning white porcelain or ceramic tiles, bathroom fixtures or collectibles. Use mild cleaners with no animal fat or oil. Fat and oil can attract dirt to the porcelain or ceramic surface. Only use absorbent, natural-fibre cloths or sponges.
Never use chlorine bleach to clean porcelain or ceramics. Bleach can damage the surface glaze, making it more susceptible to stains. If you have a white porcelain or ceramic object such as an antique that has been repaired, the repair patch may be damaged by the cleaning method used. Take the piece to a trained restoration specialist before attempting to clean it yourself.