J.B., North Billerica

A. I think you are right about the brick. Even hard brick can dust a bit, and the dust may be residue left after the bricks were laid down. Or, the bricks are a softer, common brick, which tend to dust even more.

To clean off the dust, scrub and rinse with water; there is no need for a detergent; but it will take a lot of scrubbing to loosen the ground-in dust and a lot of hosing to rinse it off. The hard brick should dust less as it ages.

As for prevention, I think your only hope is to treat the brick with Thompson's Water Seal or similar clear sealer, which might reduce the dusting. Repeat each year.

Another cure would be to mortar a row of bricks on the steps. Or, better yet, buy half-bricks, which would raise the steps less.

The trouble with putting anything on the steps is that it will make the first step higher and the top step lower, which is a hazard to anyone ascending or descending the steps, because they are uneven in height. You could correct this by putting half-bricks on the stoop or porch at the top of the steps, if it is also limestone or masonry.

Q. Some wet wood left a brown stain on my limestone hearth that I am reluctant to treat for fear of damaging the limestone, which is not shiny or polished in any way. What will work?

M.O., Derry, N.H.

A. Try straight bleach, or 1 part bleach and 1 part water. If it works, fine, but you may have to cover the whole stone with bleach to get an even result. Wear skin and eye protection when working with bleach, and use plenty of ventilation. If the bleach fails, try muriatic acid. This attacks lime, and may work off the stain. Mix the acid half and half with water. Always pour acid into water. If you do the opposite, the acid may splash out. Take similar precautions when working with acid as you would for bleach.

If these fail, sand with medium to fine sandpaper. This will not hurt the limestone, but you will probably have to sand the entire hearth to get an even finish.