Cloudy, yellowed headlights aren't a cleaning problem — the polycarbonate lens itself has degraded. Every headlight leaves the factory with a UV-protective coating, and after years of sun, road grit, and (on the coast) salt spray, that coating breaks down. The bare plastic underneath then oxidizes: it yellows, hazes, and scatters your light instead of projecting it.
That scatter is the part that matters. Oxidized lenses can cut usable light output dramatically, which you feel as poor night vision on unlit Nova Scotia highways long before the lenses look truly bad in daylight. Here's what actually fixes it, what it costs, and where DIY fits.
Why headlights fog in the first place
Modern headlight lenses are polycarbonate — light, impact-resistant, and highly vulnerable to UV. The factory applies a hard UV-blocking clear coat, and everything is fine until that coat fails, typically somewhere between 3 and 7 years depending on sun exposure, parking habits, and climate. Coastal conditions accelerate it: salt spray is mildly abrasive and holds moisture against the coating.
Once the coating fails, oxidation of the bare polycarbonate begins and compounds. This is why headlights seem to go from fine to foggy quickly — the protection failed gradually and invisibly, then the damage became visible fast.
The toothpaste trick and DIY kits, honestly assessed
Toothpaste is a mild abrasive, so scrubbing with it genuinely removes a little surface oxidation — for a few weeks. It can't level deeper degradation, and it strips whatever protection remained, so the lens re-oxidizes faster than before. As a photo-day quick fix, fine; as a repair, it makes things worse.
Drugstore restoration kits are more capable: sanding discs plus polish can restore real clarity. Their weakness is the final step. Most kits either include a wipe-on sealant that lasts months, or nothing at all — and a freshly sanded lens with no UV protection is bare plastic in full sun. This is why kit-restored headlights so often fog again within 6–12 months: the polish worked, the protection didn't.
What professional restoration does differently
A professional restoration wet-sands the lens through multiple progressively finer grits to remove all the oxidized material and level the surface, machine-polishes it back to optical clarity, and then — the step that determines longevity — applies a durable UV-protective seal to replace the factory coating. Done properly, the result lasts years, not months.
At YK Auto Detailing that's a 60–90 minute job done in your driveway anywhere in the HRM. Both lenses, sand, polish, seal. Text a photo of your headlights to +1 (782) 234-7411 for a firm quote.
Restoration vs. replacement: the math
New OEM headlight assemblies commonly run $300–$1,000+ per side on recent vehicles, plus installation — and aftermarket units often fit and perform worse than a restored original. Restoration costs a small fraction of one assembly and, with a proper UV seal, delivers years of clarity. Replacement only wins when the lens is cracked, the housing leaks moisture internally, or the reflector/projector inside has degraded — problems polishing can't reach.
There's also a safety-inspection angle: badly deteriorated or damaged lamps can be flagged at inspection time, and more importantly, they're a genuine night-driving hazard on this province's unlit rural roads well before any inspector sees them.