I am looking for some advice on how to shine up a Hoover Convertible's Hood. After sanding it to remove the gouges and scratches, I have tried many polishes and waxes, including Scratch Doctor, Turtle Wax, SEARS Brand Car Polish, and Meguiars Clear Plastic Polish, none of which have been effective. Even after multiple applications of these polishes, I am still stuck with a finish that is scratchy and dull from sanding. Is there a polish I can get that will effectively smooth and shine up the plastic?