Q: We recently bought a condo that has a fireplace with a bluish-gray marble surround and hearth. The previous owners had dogs and cats, and we suspect the animals are responsible for all the scratches (and a few gouges) in the hearth. Is there anything we can do to minimize or get rid of this problem? I was considering water-based clear polyurethane or a marble sealer. Is there anything that can be put on the gouges (they are showing white) that will blend in the color?

A: Ted McFadden, author of the "Stone Care Guide," says pets are usually not the cause of scratches on a hearth, though it is not unheard of. The usual culprit? Heavy decorative objects that were moved across the surface. The only way to remove the scratches and make the marble surface look like new is to have it professionally refinished. He says that the entire process can be performed in a couple of hours.

If refinishing is not desired, one thing that can be done to minimize the scratches is to apply a color-enhancing sealer. This will darken the white scratches and blend their color in a little to the existing surface. The effect of color enhancer can wear off over time, however. Knowing that this is marble is important. If the surface were actually limestone, it would darken, requiring the application of the color enhancer to the entire hearth.

Q: There's a stone bench-like hearth in front of my gas fireplace. It has a lot of stains on it — some I think are paint. How do you remove such stains?

A: Knowing the type of stone is important when it comes to stain removal. A good degreasing will remove most dirt, soil, and oil-based stains. McFadden says paint stains can be removed using acetone. Some stone hearths have a shiny coating. He warns that using acetone on a coated surface will damage it. Solvents will not damage most stone surfaces, but to be safe, test it in an inconspicuous area first.

Rob Robillard is a general contractor, carpenter and editor of AConcordCarpenter.com.