In this Q&A, we'll explain how to make your marble countertops shine again
The marble countertops in the bathrooms in my son's house have become spotted and dull. How can he get the shine back?
—Clair Lovell, Littleton, Colo.
Kevin O'Connor replies: Chuck Muehlbauer, the technical director for the Marble Institute of America, suspects the dulling is caused by chemicals like abrasive powdered cleaners, alcohol, and acid-based tub and tile cleaners.
He says you can apply an acrylic paste wax and buff it to a shine, but that could become something of a maintenance chore if the countertops are used a lot. Your other option is to hire a professional stone-restoration contractor to resurface it in place. The contractor would probably bring back the shine using a polishing compound and an angle grinder fitted with polishing pads, then he'll rub in a sealer, which your son should reapply periodically to protect against further chemical attack.