Fiberglass tubs are a popular choice because they are easy to install and maintain. Their seamless surfaces make them a breeze to keep clean and allow them to resist mildew build-up more easily than bathtubs constructed from other materials. However, like cast iron and porcelain bathtubs, fiberglass units can become stained. Maintaining a regular cleaning schedule and applying a little elbow grease are the best ways to care for your fiberglass bathtub and remove any unwanted dirt and stains.
Create a cleaning mixture by adding a small amount (1/4 cup) of mild detergent or all-purpose household cleaner to a gallon of warm water.
Use a soft cloth to rub the cleaning solution into the stained area. If stain remains, you will need to create a mildly abrasive cleaning mixture.
Mix together baking soda and just enough water to create a paste. Using soft cloth, apply the paste liberally to the stained area. Rub the paste into the stained area using a small circular motion. Use a toothbrush to scrub hard to reach cracks and crevices.
Rinse the area thoroughly using warm water. If the stain remains, create another paste mixture using tri-sodium phosphate (TSP) and water.
Apply the TSP paste liberally and scrub it with a soft cloth or toothbrush. Rinse thoroughly with warm water.
Apply a car wax, such as Turtle Wax, to help your fiberglass tub surface resist future stains.