Q. My new fireplace has a limestone cap on the hearth, which is about 18 in. from the floor. It is a great seat, but when I sit on it my pants pick up a chalky residue. Should I clean it with water and then seal it? What kind of sealer should I use? Please advise.

A. It sounds like you have an unpolished limestone hearth. This is a porous material and should be sealed both to protect it from stains and to eliminate the chalky residue. Buy a clear penetrating stone sealer from a home center, ceramic tile shop or stone yard. Penetrating sealers are designed to soak in, leave no surface film and minimally affect the look of the stone. Still, apply the sealer on an inconspicuous area to be sure you like the finished look.

First remove dirt, using either soap and water or a specific product recommended by the sealer manufacturer. Rinse thoroughly and let the stone dry overnight.

Apply the sealer with a paint roller or brush. Many sealers are flammable, so do not have a fire going while you do this. Also be sure you open windows for good ventilation. Apply liberal coats so that the surface stays wet for several minutes. Wipe up any standing puddles after a few more minutes. Read the directions that come with the sealer, as a second coat may be required soon after the first.