Many homes are installed with fiberglass showers because fiberglass is durable and less expensive than porcelain, stone or tile. Over time mineral deposits in hard water cause milky-colored stains on fiberglass shower doors. Hard water also eventually forms scum, film and lime deposits on fiberglass. Fortunately, stained fiberglass showers can be restored with acidic cleaning solutions. Remove the stains as soon as possible to prevent the stains from becoming permanently etched onto the fiberglass shower.
Dampen a nylon sponge with undiluted lemon juice. Citric acid is effective at removing hard water deposits and rust from fiberglass.
Scrub the stains with the sponge. Apply more lemon juice to the sponge, and scrub the fiberglass until no more stains remain.
Mix 6 tbsp. of baking soda with 1/2 cup of warm water in a bowl. Baking soda paste is a safe and effective cleaner for fiberglass showers.
Dampen a cotton cloth with warm water. Dip the damp cloth into the baking soda paste. Scrub the fiberglass shower with the cloth and paste.
Rinse out the cotton cloth with warm water. Wipe the fiberglass with the dampened cloth to rinse away the baking soda paste.
Apply white automotive polishing compound to scratches or dull areas of the fiberglass using another cotton cloth. Automotive polishing compound keeps fiberglass shiny.
Rub the fiberglass with a small amount of white automotive cream wax, using a microfiber rag. Automotive cream wax gives fiberglass an attractive finish.