Soapstone is stain-resistant, but some substances stain more easily than others. Because soapstone is nonporous, most stains will not seep into the countertop and can easily be washed away.
A frequent source of stains on soapstone countertops are thin, dark liquids, such as wines and sauces. Red wine and barbecue sauce are common culprits. Vinegar and other acidic materials can also stain your countertop, especially since the mineral oil regularly applied over the countertop can react with these acids.
Even water can stain your soapstone countertop. Prolonged exposure to moist environments or surfaces can cause large, dark spots to appear on the countertop. These cannot be scrubber away, since they are below the surface, but they usually disappear in a few weeks.
Most stains on soapstone countertops can easily be removed. How you take care of the stains, however, can be tricky, and the wrong cleaning method can do more damage to the countertop than you started with.
Remove stains with a piece of wet cloth and some mild detergent. Look for a detergent with a neutral pH level to avoid adverse reactions with any acids that happen to be on the surface. Do not use acidic cleansers because they can corrode your countertop's surface, and scrub only with 80 grit sandpaper. Other rough materials can scrape your countertop and leave permanent marks.
Apply a coat of mineral oil on your soapstone countertop every four to eight weeks. This will cover up any scratches and restore color to areas that have faded or discolored. A mineral oil coating usually stays on the surface for several weeks, providing a protective layer against heat, abrasion, and stains. You can buy mineral oil from most retailers and manufacturers of soapstone countertops.