there is this stuff called Pikal polish (no pun intended). It's the actual name and a great product. Used on headlight lens to remove scratches. Polishes plastic better than anything I've ever seen. I think it's from Japan but like $75 for a can. There is of course other more economical, locally sourced products.
Found a description: The Pikal® name in Japan for nearly 100 years has been synonymous with the finest metal cleaning and polishing products in the world. They have been the preferred products for collectors of ancient metal objects, museum curators worldwide, and also those who are charged with the operation and maintenance of scientific instruments that operate under high vacuum conditions. In all cases, metal surfaces must be kept clean while at the same time, avoiding abrasive damage to the surface during the cleaning process.
In summary: It can be aggressive if not careful but buffs oh so nicely. I've seen it take out some deep scratches that I would have thought would result in scrapped parts
