Unless the wood is badly damaged, all you will need to do is give the surface a light sanding. You also can use a product such as Liquid Sandpaper, which is basically Trisodium Phosphate (TSP). We suggest that you use the new synthetic TSP. Regular TSP is not biodegradable. Anyway, follow the instructions on the package and wipe on – wipe off. If there’s any gummy material such as wax on the panels, make sure to clean that off first with a detergent or wax remover. Next, use an oil-based primer on the panels and then you can complete the project with a finish coat of either latex or oil base paint – you get to choose.