Fiberglass bathtubs are easy to maintain, but you must be careful with them because they are vulnerable to scratches. When you clean a fiberglass bathtub, take the following tips into consideration.

Never use abrasive cleaners of any type on a fiberglass surface. Scouring powders, steel wool, or other abrasive scouring pads and scrapers must be avoided.

-- Liquid hand-applied dishwashing soap or liquid laundry detergent

-- All-purpose household cleaners, such as liquid 409 or similar liquid bathroom cleaner

-- Mild to moderate alkali solutions such as mixtures of baking soda with warm water, or a diluted TSP (trisodium phosphate) substitute in warm water (make sure it's fully dissolved)

-- "Spic & Span" cleaning solution dissolved in a solution of 1 tablespoon per gallon.

Make sure to apply all cleaners gently with a non-abrasive applicator such as a sponge, cloth, or brush made of nylon, polyethylene, or polyester.

Always rinse the cleaned surface thoroughly to make sure no cleaning residue remains.

For stubborn areas, such as bathtub rings, you can make a paste out of baking soda and a little water. Wet down the tub's surface and gently rub the paste onto it with a sponge, soft nylon brush, or cloth.