Taking care of marble

Sunset, May, 1987

Taking care of marble

Beautiful and durable, marble is a highlyvalued building material for countertops, fireplace hearths, floors, and a host of other uses (to read all about shopping for marble, see page 102 of the October 1984 Sunset). But despite its hearty appearance, marble can stain or scratch with abuse or improper care. Here's all you need to know to renew and maintain a marble surface.

We cleaned a soiled fireplace hearth, usinga care system that includes a cleaner, sealer, polish, and a poultice mix; key steps are shown in the photographs.

A poultice mix to suit the stain

Act fast against spills. Wash them offquickly or they'll soak into the stone.

If a stain persists, you may be able todraw it out with an inexpensive poultice mix ($15 a pound). It's not a readily available product, however; for leads, call a fabricator or distributor of marble or tile products.

Or make your own poultice, combining anabsorbent powder (baking soda, talc, or plaster of Paris, for example) with a solvent or strong liquid cleanser (such as acetone). The Marble Institute of America recommends some specific poultices for everyday stains:

Smoke, soot, cigarette stains: baking sodaand liquid bleach.

Coffee, tea, soft drinks, food: absorbentpowder with sodium citrate crystals and water.

Oil, butter, grease, cosmetics: absorbentpowder with acetone, naphtha, or mineral spirits.

Alcohol, rings from drink glasses: bakingsoda and a 6-percent solution of hydrogen peroxide.

Step-by-step: how to apply the poultice

Wear rubber gloves and eye protection;make sure the room is well ventilated. Clean the marble with lukewarm soapy water, or use a marble cleaner ($9 a pint).

For the poultice, combine ingredients toform a paste about the consistency of creamy peanut butter. Wipe down the stained area with the same liquid that you used for the paste. Apply a 1/4-inch layer of paste with a wooden or plastic spatula or spoon; don't use metal. Cover with plastic wrap, then seal all the edges with masking tape.

After 48 hours, remove the wrap. Moistenthe poultice with water and carefully scrape it off. Sponge the stone clean with water, then dry with a soft cloth. Stubborn stains may take two or more treatments; if stains are severe, you may never get then completely out.

When you're through cleaning, reseal thesurface or simply use a liquid or powder polish (available from a marble distributor, hardware store, or lapidary store). Liquids go on easily, straight from the can. Or wet the top with water and sprinkle with powder; rub with a damp, soft cloth or with a buffing pad on a power drill at low speed. This should remove any etch marks left from the poultice procedure and restore the sheen.

Caring for and restoring marble

These are the key maintenance measures.

Prevent damage. Use coasters, place mats,heating pads, or other buffers to protect a marble surface. Also, never let cosmetics with oil bases (which cause stains that can soak all the way through) or ferrous metal (which can leave rust marks) come into contact with marble.

Take care in cleaning. Periodic cleaningis a must, but it's easy. Simply wash the surface with a mild detergent diluted in lukewarm water, rinse, and dry completely with a soft cloth.

You can also turn to a liquid cleaner, butuse one made specifically for marble; multipurpose cleaners are risky. Never use abrasive cleaners, as they can cause scratches and dull the sheen. Steer clear of automobile rubbing or polishing compounds; some contain oil-base solvents that can dull or even stain the surface you mean to clean.

Fix shallow scratches. You can virtuallyerase shallow scratches by polishing as described above, but if the scratch is deep, you should probably call in a professional.

Apply a sealer? Some marble dealers recommendusing a penetrating sealer ($10 a pint) after cleaning; the sealer seeps into the pores, helps prevent stains from soaking in, and can bring back the sheen. A sealer is particularly useful in heavy-use areas; to prolong life in these places, reseal two or three times a year.

But before you buy, read the label or askif the sealer is appropriate for your type of marble and won't yellow it. And avoid using a wax-base sealer on marble flooring --the finish will likely be too slick to walk on safely.

Treat fungus or mildew. To get rid offungus or mildew in damp quarters such as a bathroom, add a bit of bleach to your detergent mix (about a teaspoon per pint). Remember: too much bleach or having bleach on the stone too long can etch the surface and dull its sheen.

Give kitchen marble special care. Useonly mild detergent in warm water--or a poultice if necessary. Never use vinegar; it actually dissolves marble, leaving a dull etch mark. A penetrating sealer is all right, but give the surface an extra day or two to dry before preparing food on it.

For a six-page brochure on marble care,send $1.35 to the Marble Institute of America, 33505 State St., Farmington, Mich. 48024.

Photo: Cleaned-up marble hearth had severe smoke and soot stains.Easy two-day process outlined at right and on pages 162 and 163 eliminated most stains, reduced others