UV light is still the worst enemy on polycarbonate or acrylic. Either use polishing compound and then sealer like Nanolex Si3D Headlight (won't grind the worst imperfections but the factory coating stays mostly intact). Or sand them thru the factory coating and then 2K clearcoat with plastic base.
I've read mixed reviews on the quality of those SprayMax products. I think this is better but don't know the availabity in the US.
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