Two approaches, and how to choose
Wet sanding
Graded abrasive discs cut the oxidized layer away, working from coarse to fine, then a compound polishes the surface back to clarity. This is the only method that reliably fixes badly yellowed, nearly opaque lenses — there is no chemical shortcut when the damage is that deep. It is also the method with real downside risk: skip a grit, or stop before the finer stages, and you leave sanding marks that scatter light just as badly as the haze did.
Chemical wipe systems
No sanding, no drill: a solvent wipe dissolves the oxidized surface and a second wipe leaves a ceramic protective layer. On light to moderate haze the results are genuinely good, and it is essentially impossible to damage anything. On a lens that has gone properly opaque it will not have the correcting power — it removes a microscopic layer, not a visible one.
The specification that actually matters
Look at what the kit leaves behind. A dedicated UV sealant or ceramic coating is what makes a restoration last. A wax protectant is better than nothing but washes off in months. Nothing at all means you are on the clock from the day you finish. Note that none of these brands publish a rated durability figure, so judge the kit by whether it seals, not by its claims.
Doing it properly
Mask generously.Tape off all the paint around the lens — two layers, extending well past the edge. Sanding discs and drill pads skip, and a sanded fender is a much bigger problem than a hazy headlight. The kits that include tape do so because this is the most common mistake.
Keep it wet, and do not skip grits.Wet sanding means genuinely wet — spray frequently. Work each grit until the entire surface has a uniform matte appearance with no glossy patches, then move to the next. Skipping a grade is what leaves marks the compound cannot remove, and the fix is to go back and start again.
Work across, then up and down.Alternating direction between grits makes it obvious when the previous grit’s scratches are gone, because you can see the old pattern disappearing.
Seal it, the same day.Clean the lens with alcohol so the surface is chemically bare, then apply the kit’s sealant properly. If your kit has no sealing stage, buy a glass or trim ceramic coatingand use that instead — it is the difference between a repair that lasts years and one that lasts a season. Then keep it protected the way you would any exposed surface, because the sun that caused this has not gone anywhere.
When to stop and replace
If the hazing is insidethe lens — condensation, a failed seal, or internal reflector degradation — no amount of external work will help, and sanding a lens that is cracked or crazed can make it worse. Look at the lens closely in good light before you start: external oxidation feels rough and looks uniform; internal damage looks like it is under glass, because it is.
