Begin by washing your vehicle with a mild, non-abrasive liquid detergent to remove any dirt or loose material from the surface. Add a cup of detergent added to a gallon of warm water. If there is mildew present, a cup of bleach may be added to the solution. Another alternative is to use a product created specifically for cleaning gelcoat, which may contain wax as well. Depending on the level of oxidation present, this may be enough to restore color and shine to your vehicle. Use a soft, clean sponge or wash mitt to avoid scratching the gelcoat as you clean. Acetone or MEK (methyl ethyl ketone) may also be used to remove any spots of grease, adhesive or wax that remain after washing. Be sure to wear rubber gloves and work in a well-ventilated area if you use these chemicals. Color restorer can also be used to treat light fading.
If a simple wash isn’t enough to brighten and restore shine to the gelcoat, your next step will be to use a polish. Gelcoat polish contains very fine abrasive particles that will rub away the dull, oxidized, pitted surface, much like fine grain sandpaper. Apply to a small area at a time with a soft white cloth or sponge and rub in a circular motion until shine is restored. You’ll need to reapply wax afterward, as it is removed during this process.
Should pitting and fading still be evident, your next step is to use an oxidation remover or polishing compound. When gelcoat has become moderately to heavily oxidized, these more abrasive products work to remove even more of the damaged surface, much as coarser sandpaper is used before moving on to a finer grit. Unless the oxidation has penetrated entirely, plenty of gelcoat is left behind to polish and seal. Wet the gelcoat surface and apply the product as you would the polish, but be careful not to rub in one area for too long to avoid going through to the fiberglass. Apply the polish again before applying wax or sealer and buffing. At this point, you should see shine and color restored to your gelcoat. You may want to rent or purchase an electric buffer to use with the polish or polishing compound, if the size of your vehicle makes doing it by hand a daunting task.
