What is the best car paint scratch remover for matalic paint.?

Depends how deep, I just had a narrowish but deep scratch on my metallic mica green Miata. Down to the primer so I had to do rubbing compound (just basic Turtle compound) with some elbow grease. Check the cloth regularly to see if excess paint is coming off, be careful. Hopefully this will move the paint into and over the scratch but will leave a very matt patch of paint. Then I used meguiars step 2 polish with a 6'' orbital polisher to polish the paint back to original shine. Took two tries but fully filled the scratch with only a slight dip seen in the paint. If it's not down to the primer, should be just able to use the polish. BTW electric polisher not needed, but boy it sure helps. Makes the car look great after winter, removes all small scratches and spiderwebs.  more