I am trying to polish my tailight and parking light lenses, but there are some nicks and dings in them that are deeper then the polish can take out I think.

Is it safe to use emory cloth or something and then go back over with the polish? I am using 3M cleaner, and then the polish. 2 step system. I know Novus makes a really good 3 step product that has a "heavy scratch remover". Maybe thats what I need?