The last stage of a typical automotive paint job is to spray a coat of clear lacquer or urethane. A clear coat finish protects the base colour coat but is itself vulnerable to weather and sun, and can eventually start to peel. Before you can spray a new clear coat, you have to remove the old one, or at least the sections that are peeling. The only way to do this is by sanding with very fine wet/dry sandpaper. Take care not to damage the underlying base coat in the process.
Mix a solution of dish detergent and hot water in a bucket and wash down the areas of peeling clear coat with a sponge. Dish detergent isn't usually recommended for cleaning a car because it dissolves wax and dries out the surface, but these qualities actually make it a better choice for washing off peeling paint than automotive detergent. You may be able to remove a significant portion of the peeling finish by applying pressure with the sponge as you rub it in a circular motion. Rinse the areas you have washed with plain water.
Cut a sheet of 1,000-grit wet/dry sandpaper in half, then fold one of the halves in thirds and soak it in water. Rub the sandpaper over the peeling paint in a circular motion, applying enough pressure to remove it without damaging the surface underneath.
Lift the paper and check your progress frequently. Stop sanding an area if colour begins to appear on the sandpaper. If a small amount of peeling finish remains in the centre of an area from which the finish has been removed, fold the sandpaper into a smaller square and sand only the peeling finish you are trying to remove.
Keep the sandpaper and the surface you are sanding wet. Frequently dipping the paper in water is usually sufficient to transfer enough water to the surface to ensure proper lubrication.
Feather the edges of the sanded area by rubbing the paper in small circles to flatten them. Attention to detail in this part of the process will ensure that the repair will blend with the rest of the surface when you spray on a new clear coat.
For extensive peeling, sand off the clear coat from the entire section of the automobile, such as the hood or a door, to get a more appearance when you respray.