I helped a friend out today by wet sanding and polishing the headlights on her recently purchased '54 plate BMW 3 series. They'd gone very cloudy and we were happy with the results. I'm aware that restored headlights can benefit from a UV sealant, but despite a lot of research on here and elsewhere, I'm unsure of which products are currently the recommended options. I've been considering Meguiars Keep Clear Headlight Coating and E-TECH Restored Headlight Clear Coat.