There are several ways to repair marble countertops, depending on the type of damage to the marble. While some damage like water stains are fairly easy to repair, other damage requires more specific efforts.
TIP: Before you use any of these methods, be sure to look at up safety tips to follow. Some of the products you'll use in these steps (such as epoxy sealant) are toxic if you inhale them, which means you'll want to use safety glasses and a face mask.
Method 1 - Waxing
Regular waxing will restore the shine to marble. Waxing will also create a protective barrier on the surface of the marble to prevent additional damage from scratches or water.
Method 2 - Varnishing
Cover the surface of the marble countertop with a coat of polyurethane varnish. Similar to waxing, applying polyurethane will create a protective barrier for the surface of the marble countertop. Also, varnish restores the shine to the marble.
Method 3 - Epoxy Sealant
For small cracks, use an epoxy sealant. This material can be found at almost any home improvement center.
Clean the surface of the countertop thoroughly and let the area dry. Apply the sealant to the cracks, using a clean damp cloth to remove any excess epoxy. Let the epoxy dry and then lightly polish to a bright sheen.
Method 4 - Tin Oxide
Use tin dioxide to repair scratches and stains to the surface of the marble. Tin dioxide can be purchased at monument stores or building supply retailers. Tin dioxide is also called grade polishing powder.
Apply the power to the marble countertop with a piece of felt fabric. Gently rub it into the surface of the marble until the scratch or stain is removed.
Method 5 - Epoxy Adhesive
For broken or chipped places on the marble, carefully remove the chip or broken piece. Thoroughly clean the area with acetone and a clean cloth. Apply a thin layer of epoxy and then carefully re-apply the chip or damaged piece. Wipe away any excess epoxy. Let the adhesive dry and then wax the area or apply polyurethane varnish.
Method 6 - Poultice Stain Removal
If the damage to the marble countertop is from calcium water stains, remove any wax or other debris from the area of the stain.
Prepare a poultice of diatomaceous earth and 50 to 70 percent peroxide (you may need to purchase the peroxide from a pharmacy; it is a higher strength than the standard hydrogen peroxide sold for home use). Mix the poultice until it is a creamy consistency similar to thick whipped cream or peanut butter.
Dampen the stain area with distilled water. Place the poultice mixture over the stain at a thickness of approximately ¼ inch. Cover the poultice with plastic wrap and completely seal the entire area. Poke several small holes in the surface of the wrap to allow for air.
Let the poultice dry for a minimum of 24 hours until it is completely and thoroughly dry. The poultice will pull the stain completely out of the marble.
Once the poultice is dry, remove the plastic wrap and carefully remove it with a putty knife, being careful not to scratch the marble. If needed, repeat the process until the stain is removed. If you do not see any change at all, the stain may be entirely set in and unable to be removed.