Sand it out.

Did you try plastic cleaner. Meguiers sold a cleaner and a polish. The cleaner is what cut the scratches.

Try some toothpaste, since it's handy and basically free.

Wenol works good too.

If that all doesn't work, you need to sand it out. 1200, 800, 600 grit wet sanding on a small block to keep it level.

Good post on this:

https://board.moparts.org/ubbthreads/show...rue#Post7714490