Q I have white aluminum siding on my house that is about 10 years old. Over the years it has become dull and old-looking. Is there anything that will clean it and bring back the color, or will I have to have it painted? -- J.N. A Aluminum siding can be painted, and there are special paints on the market for that purpose. However, in many cases all the siding needs is a good cleaning. Even siding with a finish that is oxidized or powdered at the surface can often be restored to good appearance if the proper cleaning methods are used.

Keep in mind that new paint also will get dirty and there are other possible problems such as peeling and flaking of the new paint, in addition to the extra expense of painting. In short, unless a color change is wanted, the effort to clean the existing siding is a good first step. The effort won't be wasted even if it doesn't work out, because cleaning is a necessary first step to painting.

Some professional painters have pressure-washing equipment that can do the work effectively, but do-it-yourself pressure cleaning equipment can also be rented. A method recommended by some siding manufacturers for light cleaning is to wash the siding much like a car is washed, using a soft-bristle brush such as an auto-washing brush and a solution of regular household detergent. Rinse thoroughly with clean water from a garden hose.

Some home centers also sell special aluminum-siding cleaners containing heavy-duty detergents. Specific directions for those should be followed carefully. Q My glass shower doors are a mess. Very stubborn hard-water stains and soap scum have dulled the once-shiny metal frames of the doors. No commercial product has helped. What can be done to make the doors look like new again? -- S.A.H. A First, go over both the glass and metal frames with dampened baking soda, then scrub with a terry cloth rag wrung out in white vinegar. Let this solution stand on the surface for a couple of hours.

For particularly stubborn stains go over the surface with a fine stainless steel wool pad. Rinse with clear water and polish with soft cloth.

Another solution you can try is to mix 1 cup of trisodium phosphate with 2 tablespoons of alum. Add enough water to make a paste and apply to the surface. Scrub with a soft cloth, rinse well and polish. If necessary, use a fine steel wool pad to scrub the surface in a second application.

If the metal is corroded nothing will restore the surface. Q I have a brass lamp. The original surface has become dull and it is pitted. Is it possible to restore the finish and remove these pitted marks? -- S.A. A If the pits are just surface marks, polishing with a good brass polish may be all that is necessary.

If you can't remove the marks yourself, take the lamp to a brass specialty shop that does repairs, polishing, etc. If they can't polish away the marks, they can fill the pits, using a process that's fairly expensive but that does make brass look as good as new.

After the brass has been filled and polished, have the shop give it a coat of lacquer that will help prevent the brass from pitting for some time. Q I have a pair of very fine pewter mugs. The lustre of the finish has become dull and ugly over the years. How should these be cleaned, so I can restore the original finish? -- G.S.M. A For removing general stains on pewter, wash with soapy water; dry. Or rub with a cabbage leaf.

For more stubborn stains, rub with fine steel wool and olive oil, or with a paste made from a mild abrasive powder and olive oil. To remove grease stains, rub with shellac solvent (methylated spirits) and wash. If this method fails, consult a professional for restoration of pewter. 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.