How can I clean the black soot off my marble fireplace hearth?

Several products are designed specifically for cleaning soot and carbon build-up from marble. Contact your marble supply house. Be sure the product is not an acid; apply it per the manufacturer’s directions and allow it to sit on the marble for 10–20 minutes. Agitate lightly with a soft-bristle brush and thoroughly rinse it from the surface. Repeat this procedure if the first application does not clean all the soot from the marble.

TIP You may first want to try a solution of ammonia and water. Apply the solution and agitate with a soft bristle brush. Rinse throughly.