Q: Can the surface of a dingy, scratched molded-fiber glass shower and tub enclosure be restored? We have recently bought a 20-year-old house and the bathroom shower and tub enclosures are a mess. I would appreciate your advice.

A: How to clean and restore fiber glass fixtures is a frequent question. Even so, the information warrants repeating.

For general cleanup and stain removal, try removing as much discoloration as possible with this formula: Mix 2 tablespoons of turpentine (not paint thinner) into 1/4 cup of regular table salt. Pour the mixture onto the surface and scrub vigorously with a nylon-bristle brush. Wipe any excess cleaner off with a paper towel.

Make sure you have plenty of ventilation in the room and wear rubber gloves. Any rags or paper towels that absorb the mixture should be air-dried and disposed of in plastic bags to avoid posing a fire hazard.

Another method of cleaning stained fiber glass is to use automatic dishwasher detergent or water conditioner, such as Calgon. Fill the tub or shower with about an inch of water. Then sprinkle an even layer of the granules over the surface and let them sink to the bottom. A day later, drain and use the paste that's left in the bottom to scrub away dirt and stains.

For walls, make a paste by mixing the granules with a small amount of water and apply the thick substance to the surface. Let this set overnight before rinsing with clear water.

Some of my readers have suggested using oven cleaner. This method should be tested first in an inconspicuous area to ensure that the surface of the fiber glass will not be marred. When using oven cleaner, spray the surface and let set for several hours prior to rinsing.

Several applications of either the dishwasher paste or oven cleaner may be required before the fiber glass color is restored.

There are also nonabrasive commercial cleaners on the market that contain ethylene diaminetetra-acetate (EDTA) that are effective fiber glass cleaners, such as GelGloss. Marine stores carry a range of products for use on fiber glass boats that can be used on fiber glass tubs and showers just as effectively. Some of these should be used with a buffer for best results.

Even after the staining has been removed, fiber glass surfaces may remain dull and scratched. A three-step process can restore the shine. Buffing the surfaces with a polishing compound will polish out small scratches. Applying a coat of sealer will help fill any remaining surface scratches, making the finish even smoother. And, finally, rubbing wax onto the sealed surface with a buffing pad will add shine and luster.

In cases of severe scratches, you may have to start by using 600-grit wet/dry sandpaper, wetting with water and a few drops of hand dishwashing liquid as a lubricant. Do this prior to the initial buffing.

Surface cracks and gouges, compared with scratches, are more difficult. Check your local home center for fiber glass repair kits, which come in various shades and include gel and a hardener to fill deep gouges. Follow manufacturer directions carefully. If unavailable in your area, a Match 'N Patch Kit can be ordered from Surface Specialists Systems Inc., 5168 County Club Dr., High Ridge, Mo. 63049; phone: 314-376-4468.

Large structural cracks that go through the fiber glass panel require the attention of a professional. Check auto body shops or boat repair specialists for assistance in finding someone.

To avoid scratches and surface problems in the future, never use abrasive cleansers or strong chemical solutions on your fiber glass fixtures. Use bathroom cleaners such as 409, Fantastik or Comet's Bathroom Cleaner without bleach. For occasional deep cleaning, make a paste of baking soda, apply to the surface and leave overnight prior to rinsing with clear water.

Send e-mail to copleysd@copleynews.com or write to Here's How, Copley News Service, P.O. Box 120190, San Diego, Calif. 92112-0190. Only questions of general interest can be answered in the column.