Q: We recently bought an older home that has ceramic tile countertops in the kitchen. The tile surface is attractive and in good shape, but the grout between is stained.

I have tried numerous cleaners and bleaches with no success. Do you know of a method to clean grout without replacing it? If I do have to replace the grout, is there a product I can use that will help prevent staining of the new grout? -- J.H.

A: Ceramic tile countertops in kitchens are subjected to the worst possible household stains, and the grout joints are particularly susceptible to them.

The Tile Council of America recommends applying a thick paste of scouring powder and hot water, letting this paste stand for five to 10 minutes. If stains remain, apply undiluted bleach for at least five minutes, rinse well and dry.

If this fails to lighten and brighten your grout, you should consider regrouting the surface layer. Tile dealers have a special tool you can use to remove about one-fourth of an inch in the grouting so new grouting can be installed over the old.

For future protection, apply a sealer over the new grouting or cleaned grouting. There are two types of sealers on the market.

The topical variety is usually acrylic-based -- penetrating sealers, often silicone-based, are absorbed into the grout. However, some tile manufacturers do not recommend applying a sealer over their tiles, which means using great care in applying the sealer to the grout only, carefully wiping away any excess sealer solution from the tiles.

These sealers need to be renewed from time to time and are effective in general, but at times they are not satisfactory in combating the staining caused by fats and oils that you will have in the kitchen.

There is one product recently introduced by Glaze 'N Seal (Glessner Corp., 1301 Sansome St., San Francisco, Calif. 94111), which is an acrylic grout sealer that the manufacturer says will protect against organic stains, including cooking oil, grease and beverages.

The sealer can be applied to untreated grout only and may darken or produce a slightly wet appearance on some grouts. Care should be taken during application so that none of the sealer is allowed to dry on the tile surfaces.

Another new product on the market is Latapoxy SP 100, a stain-proof grout that is available in a wide range of colors. The manufacturer of this product (Laticrete International Inc., One Laticrete Park North, Bethany, Conn. 06525) recommends it for kitchen counters as well as tile floors, as a stainless grout that is uniform in color and resistant to staining caused by most foods, beverages and cleaning agents.

Q: Recently we completed a deck using pressure-treated wood for the construction. I have been told to put a preservative finish on it to make the deck last longer.

Is this important with pressure-treated wood, or is it largely decorative? If it is useful, what type of finish do you recommend? -- J.L.

A: Unfortunately, it is a common assumption that pressure-treated wood is treated to resist all types of damaging elements. Although the treated wood resists damage from wood-boring insects, it is still vulnerable to water damage. There are treatments that will help protect the wood and enhance the appearance.

Koppers Co. produces two such products: Rain Coat is a sealer designed for use on pressure-treated wood, and Deck Stain is formulated to tint and protect all types of wood used outdoors.

Thompson's Water Seal and Wolman's Rain Coat are also popular water repellents used to help prevent damage. A sealer of this type is easy to apply, and probably something you can do yourself.

Newly installed pressure-treated wood should be allowed to season for one to three months before treatment. Be sure the deck is clean before you apply a sealer.

If it is stained, you can clean the surface with diluted chlorine bleach or a commercial deck cleaner such as Wolman's Deck Brightener. When the deck is clean and dry, apply the water repellent or sealer.

Your deck should be treated with a water repellent about every two years. You can test the surface by splashing a glass of water against the wood. If the surface absorbs the water, making the wood noticeably darker, then the wood is vulnerable and needs the immediate protection of a waterproofer. If the water beads up, or doesn't absorb into the wood, the surface is protected.

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.