Cleaning, protecting and restoring fibreglass, polyester, grp or gel coat. This article applies also to motorhomes and caravans.

Pollution, acid rain, salt and bird droppings penetrate unprotected surfaces, destroying the shine and opening larger pores. The process is accelerated by the UV radiation in sunlight.

Avoid detergents that contain bleach or abrasive compounds.

Avoid car polishes – most of them contain abrasives.


Rinse off salt and dirt with clean fresh water.

Use BoatSheen Polymer Wash & Wax concentrate to provide a slick hydrophobic surface from which water just sheets away. Add a capful to a bucket of water or apply by pressure washer.

For surfaces that have been waxed with carnauba wax, use BoatSheen Carnauba Wash & Wax concentrate to top up the wax. Ideally, use soft water to avoid lime spots and wipe dry with a microfibre cloth or chamois wash leather.


Protect the surface with BoatSheen Glaze, Performance Boat Wax or Best Brazilian Boat Wax.


Use minimum abrasion to restore a shine. Use BoatSheen Pre-wax Colour & Shine Restorer to restore colour and shine without damaging the surface. This lifts out dirt and impurities, removes fine scratches, salting, oxidation and old wax residues to restore the true colour. Reserve compounding for removing scratches and abrasion marks. Compounding works by removing part of the surface, and repeated use thins the gel coat, potentially exposing the glass strands and leading to ‘osmosis’ damage. Always follow up by applying wax or glaze to protect the surface.

If machine polishing, use light pressure and don’t allow the surface to get hot or it will be permanently damaged. Techniques and machines used for car bodywork are generally too aggressive for fibreglass and can cause permanent damage. For regular polishing, use an orbital polisher in preference to a rotary machine – this works on a cam which mimics a hand action, preventing holograms and buffer trails. Use a rotary sander-polisher for compounding and sanding.

To remove stuck-on contamination like tar, industrial dust, tree sap and overspray, use BoatSheen Eraser Clay and Lubricant. Eraser Clay is a dense mineral resin mixture which is used with the lubricant to glide over the surface, picking off anything stuck to it. It is a non-abrasive process that produces an extremely high grade, smooth finish. It will not remove nor create scratches.

For worn and abraded fibreglass, use BoatSheen Clean Cut Compound. This is suitable for hand or machine use. When repairing fibreglass, ensure that all traces of wax have been removed and abrade the surface to provide a key for the repair.