Q. We recently bought a home with a flagstone floor in the entryway. This has a rough texture and I am not sure how it should be cleaned, which it needs badly, or how it should be maintained. I have found very little information on flagstone. Can you give me any suggestions?

A. Any existing sealer should be stripped from the surface. Ammonia diluted with water will strip most sealers. Then scrub the surface with a stiff non-wire brush and a solution of TSP -- one part mixed with nine parts of water. Let dry thoroughly.

The best way to treat the cleaned surface is to give it a coat of regular penetrating floor sealer. This should be a sealer of low viscosity and not more than 25 percent solids.

One coat of a sealer should suffice until it appears to be worn away, which should not occur for several months, depending on the amount of traffic. Then it should be patched without going over the whole floor, unless the area is small.

If the flagstone is a light color, regular floor sealer may give it a slight amber tint. If you don't want that, use a colorless solvent-type terrazzo sealer.

A sealer will not only enhance the appearance of your flagstone, it also will make it easier to maintain.

A. I live in a high-rise condominium building where all the bathrooms have fiberglass tubs and shower stalls. These are quite difficult to clean and a lot of unit owners complain about them. A lot of us are afraid to use cleaners such as scouring powders.

Can you recommend a safe cleaning agent?

A. You are wise to avoid any abrasive cleaners because they scratch and damage the surface of the fiberglass, adding to your problems. You should also be careful with strong solvents.

For regular cleaning, use a mild liquid cleaner such as Spic and Span, 409 or Top Job. Or you can use a nonabrasive cleaner such as Bon Ami or Soft Scrub.

For stained areas, use these products full strength and let set for 20 minutes to half an hour, then rinse with clear water.

For more stubborn stains, here are some suggestions: Use one of the liquid cleaners made for automatic dishwashers. Apply full strength and let set overnight, then rinse with plenty of clear water.

For smudges and spots, try a waterless hand cleaner called Mintex, made by Savogran. Rub Mintex on the smudges with your fingers, then wipe with a clean, soft rag.

Another cleaner made specifically for fiberglass is Gel-Gloss, which is available at housewares stores and marine supply stores. A boat supply store also is a good place to check for cleaners recommended for fiberglass boats (compounds that can be buffed). These will do the job on your fiberglass shower just as well as they clean the hull of a boat.

Q. I have a large mirror that has some scratches and dark spots. They are not terribly noticeable. Is there any way I can repair them myself?

A. If the damage is not too bad, there are some techniques that might work.

First remove the mirror backing. On discolored or tarnished spots on the back of the mirror, use the abrasive side of a kitchen sponge to scrub off the discoloration. Try to avoid enlarging the affected area.

Patch these spots with a piece of aluminum foil. No adhesives are necessary; the patch will be held in place by the mirror backing. Adhesives or tape can damage the silver backing.

Tiny spots of discoloration can be carefully removed and the bare spots touched up with silver artist's paint. This is a good method for minor scratches that do not have discoloration.

If the results of these techniques are not satisfactory, your best bet will be to have the mirror professionally resilvered.

Send inquiries to Here's How, Copley News Service, P.O. Box 190, San Diego, Calif. 92112-0190. Only questions of general interest can be answered in the column.