Q. I recently paved my yard with common red brick. The employees of the contractor poured a wet cement mix and sponged the grout between the bricks, apparently not rinsing the sponge enough to leave the brick clean.

When the brick dried, the natural red color of the brick became a dull grayish color. Can anything be done to restore the natural color of the bricks? -- M.C.

A. To remove the dried residue of mortar, first try cleaning the brick by scrubbing with a solution of half cup of trisodium phosphate and a half cup of household detergent dissolved in one gallon of clean water.

Scrub with a stiff fiber brush -- do not use a wire brush. Thoroughly wash off all cleaning solution, dirt and mortar crumbs, using clean pressurized water.

If the condition still persists, use a solution of muriatic acid recommended for removing hardened mortar. Mix one part acid to 10 parts clean water.

Use extreme caution when dealing with acid mixtures. Mix in a nonmetallic container and pour the acid into the water, never water into acid. Be careful to avoid splashing. Wear old clothes, rubber gloves and goggles.

Presoak the area, flushing off all loose mortar and dirt. Soak with plenty of water before applying the acid, so the acid and dissolved mortar will not be drawn into the face of the brick.

Apply the acid solution with a rag mop so it can soak into the brick. Allow it to act for a few minutes, then flush off with plenty of clear water. Scrape off any globs of hardened cement with a putty knife or screw driver.

You may want to test the acid mixture in a small, inconspicuous area first, since minerals found in brick vary from area to area, and some cleaners can react with them in unexpected ways.

For example, an acid used on bricks with high copper content could turn them green. Acid solutions should never be used on light-colored brick. After cleaning, neutralize the acid with ammonia and rinse again.

After the brick is thoroughly clean and dry, apply a masonry sealer for protection. These are available in either clear or colored solutions that can enhance the red color of your brick.

Q. How can I remove dried paint that was splattered on our patio when the house was painted?

A. The most important step is to act fast. For oil-base spots and stains, try a rag dipped in mineral spirits, then rinse the area.

Latex paint is water soluble for up to 24 hours. Soak a rag in water and scrub the spot.

If the paint has dried for more than a day, try a commercial enzyme cleaner such as De-Solv-It, Oops or Goof-Off, which are available at housewares or hardware stores.

If your patio is concrete you might try a regular paint stripper-remover. Test in an inconspicuous place first.

Q. How do I remove some old adhesive vinyl strips that were put in the bottom of our fiberglass shower some years ago?

A. Carefully remove as much of the material as you can with a razor, being careful not to cut too deeply into the fiberglass surface.

There are a number of products that you can use to dissolve the remaining adhesive residue. The one that works successfully will depend on the chemical makeup of the adhesive.

Try spraying either Spray 'n Wash or Endust on the adhesive residue. This can also be tested before any removal of the strips, as sometimes the adhesive underneath will soften and strips can be lifted off without scraping.

Let set until the adhesive is softened, then scrape with a plastic knife or spatula -- one that won't mar the fiberglass finish.

Another method is to dampen paper towels with isopropyl alcohol. Lay over adhesive and cover with a plastic film to prevent drying.

After the adhesive is softened, pick it up with strips of masking tape.

A 50-50 mixture of xylene and isopropyl alcohol finishes the cleanup; alcohol mixed with solvent reduces smearing often created when using a solvent alone.

Another product that can be used successfully is photographic film cleaner, available in most camera stores. This works fast because it evaporates quickly and should be used only when plenty of ventilation is provided.

Other solutions that can be effective are lacquer thinner, acetone, rubber cement solvent, 34X and naphtha, or methyl ethyl ketone.

Test first in an inconspicuous area to assure that the solutions will not mar the fiberglass finish.

Q. Can we install 24-by-24 floor tiles on our concrete basement floor, or do we have to install standard 12-by-12 floor tiles in order to allow the concrete to breathe? -- G.D.

A. Regardless of the type of material you are using, it is important that the manufacturer has approved the floor covering for below-grade installation.

Both vinyl tile and sheet flooring can be laid directly on concrete if they are approved for this type of installation, provided that the concrete slab isn't damp.

If you suspect moisture problems with a slab, have the installer put down a vapor barrier and a plywood or hardboard subfloor before laying the flooring.

Q. We have a bedroom that has been painted three or four times in the past with no problems. Recently, bubbles have started to appear, removing all paint down to the plaster.

I have used the same brand of paint before, and there have been no problems.

The bedroom shares one wall with the bathroom; the others are exterior walls. What's causing the problem? How can I correct it? -- D.I.L.

A. It is likely your problem is caused by moisture inside the wall. This could come from a leak in the roof, a plumbing problem or something of that nature.

Often the path of water traveling from small leaks is very hard to detect. However, you will have to find the source of the moisture and correct it or your wall will be damaged even more.

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.