Fiberglass is widely used in the manufacture of pleasure boats and RVs. This is because it is easy to use and is less expensive than steel or wood and it lasts a long time. However, fiberglass oxidizes similar to steel, and over time will become weathered and lose its shine. Restoring weathered fiberglass is not that difficult.
Restore the Weathered Fiberglass
Inspect the fiberglass and determine the extent of oxidation that has occurred.
Clean the fiberglass with soap and warm water.
Rinse the fiberglass with clean water to remove soap residue and let dry.
Rub the surface with a polishing compound to take off the oxidized layer. Polishes have abrasives in them and will act like fine sand paper. If the oxidized layer is heavy you may need to find a heavy duty polish.
Let the polish dry, and then buff it off to expose the clean surface. If the fiberglass is not shiny at this point, it is likely because the gelcoat is pitted. When oxidization occurs, microscopic holes are created in the gelcoat. Those holes must be filled to restore the shine.
Apply a sealer to fill the microscopic holes, which will restore the shine.
Repeat the process as needed. You may need to perform the maintenance once a season.