When cleaning fiberglass showers, clean the glass after every shower using mild soaps and white vinegar, scrub it with a nonabrasive material, and use baking soda or borax to remove stains. Also, avoid prolonged contact time with commercial cleaners. If there are excessive mineral and soap scum deposits on the fiberglass, use an oven cleaner that emits no fumes.
Clean a fiberglass shower after every use with a squeegee to prevent mineral and soap scum accumulation. To remove this accumulation, use mild cleaners such as dishwashing soap or shampoo instead of harsh cleaners and abrasive scrubbers, as these cause scratches in the fiberglass that result in a dull and damaged surface. Mix the mild cleaners with white vinegar in a spray bottle, spray the mixture on the fiberglass, and scrub it using a soft sponge.
If using baking soda or borax, sprinkle these substances directly on the fiberglass, or use a damp sponge to apply them. If the stain is stubborn, place a paper towel soaked in vinegar over the baking soda or borax. Remove the stains with a nylon brush, rinse the area, and dry the fiberglass using a soft cloth or squeegee.
When using commercial cleaners, don't leave them on the fiberglass for periods longer than specified. Otherwise, the acids in these products may scratch the surface. Use oven cleaners that emit no fumes, as the lye present in regular ones can harm the fiberglass surface.