Things You'll Need
Food-grade mineral oil
Soapstone is a natural quarried rock that has a smooth feel almost like running your hand across a bar of soap, which is where the name comes from. Soapstone is stain- and heat-resistant, but can scratch easily. Typically, stains on soapstone are only on the surface and do not penetrate into the stone. A deeper, darker color does not indicate the sink is dirty; soapstone colors deepen as the sink ages. Scratches or chips in a sink will harbor bacteria and collect dirt and food particles, making restoration necessary.
Rinse the soapstone sink with water. Squirt dish soap onto a damp sponge and wipe down the sink to remove dirt and stains. Rinse the sink thoroughly with plain water.
Wet a piece of 180-grit sandpaper if a soapstone sink scratch or chip is deep. Rub the scratch or chip, first sand across the scratch and then follow the line of the scratch when sanding.
Run water over a sheet of 320-grit sandpaper. Sand chips smooth. Rub the sandpaper in the direction of the scratch until the soapstone scratch is no longer visible. If you removed a deeper scratch with 180-grit sandpaper, rub the sanded area with wet 320-grit sandpaper.
Wet a piece of 600-grit sandpaper and sand the area a third and final time to blend the sanding in with the surface of the soapstone sink. Allow the sink to dry completely.
Dip the corner of a clean, cotton rag into food-grade mineral oil. Rub the mineral oil into the soapstone surface to create a protective coating. Reapply food-grade mineral oil every four to six weeks to maintain the protective coating.
Mineral oil will darken the soapstone; this is normal.
Do not drag glassware or china across soapstone; you will scratch the glasses or china. If the soapstone sink is cracked or broken, replacement is necessary.