Fibreglass surfaces, like other surfaces, are susceptible to stains. From rust stains to soap scum, fibreglass attracts it all. There are several products you can use to clean fibreglass, including acetone--a chemical that is also used to remove nail polish and other paints. Acetone removes not only dirt and grime from your fibreglass surfaces, but also any set-in stains like rust and pen marks.
Put on a pair of latex gloves to protect your skin from the acetone.
Pour 5 tbsp of acetone into a bucket.
Dip a white cotton cloth into the acetone. Remove the cloth and wring out excess acetone.
Wipe the fibreglass surface with the acetone-soaked cloth.
Apply light pressure to remove any stains from the fibreglass surface.
Wet a white cotton cloth with warm water from a sink. Wring out excess water.
Wipe the fibreglass surface with the damp cloth to remove acetone residue.
An automotive white polishing compound can be applied to fibreglass surfaces to fill in any scratched or dulled areas. Apply the polishing compound with a clean cloth and follow the treatment by applying an automotive white cream wax. Buff the waxed area with a clean towel. These treatments should be applied twice a year to scratched or dulled areas.
Acetone is highly flammable--do not use the chemical around any heat source or open flame, and do not smoke while using it. Work in a well-ventilated area. Do not pour acetone down the drain or allow it to come in contact with plastic drain grates. Leave acetone to evaporate; cover it with a screen to protect wildlife. Do not use an abrasive cleaner or scouring pad on the fibreglass surface. Abrasive products will scratch, discolour and dull the fibreglass surface.