Sylvania Headlight Restoration Kit is the pick. It finished first on both the
salvage-yard headlights and the controlled polycarbonate panels, and it is the
only kit that made a badly oxidized lens look genuinely new. That comes at a
cost in effort: 21 minutes per headlight through a surface activator, three
grits of wet sanding, a clarifying compound, a second activator pass and a
wipe-on UV clear coat. At $22 it is the joint most expensive kit here.
For a coating meant to last, Cerakote is the better buy at $17. It was second
in both rounds, needs 15 minutes and no drill, and its cured ceramic layer is
very difficult to scratch — noticeably harder than the Sylvania coating, which
is the one place Sylvania gives ground. The value pick is 3M at $15: its P500
drill discs cut through the damaged polycarbonate in 20 seconds, the fastest
in the test, and removed the deep scratches better than anything else. Because
that kit stops at rubbing compound, pairing it with a separate UV coating gets
close to the best of both. Rain-X, at $21 and nine minutes, cuts well but its
sealant cures soft and inconsistent.
The lesson from the bottom of the field is that abrasive strength decides
almost everything. Rust-Oleum sands by hand and does clear the oxidation in 11
minutes, but its coating is not as smooth or transparent as the leaders. Armor
All is the quickest kit here at seven minutes and the cheapest at $13, and its
solvent is genuinely effective on surface grime — on lightly hazed lenses that
may be all that is needed — yet on heavy oxidation the wipes leave the damage
in place. Meguiar’s finished seventh in both rounds for the same reason: its
coating covers damaged polycarbonate rather than removing it, and stays soft
once cured. If the headlights are badly yellowed, buy a kit with real
sandpaper or sanding discs in the box.