That's for slight pitting. To correctly redo it you need to use flexible molding filler. It's sort of like Bondo in the sense that you use it to fill in low spots and sand it to make it even. When your done you paint it with special rubber/trim paint. It takes a while depending on how bad they are but they come out just like they were from the factory when done correctly. If you have never done that type of thing I would suggest getting help or just going for the covers.