Polishing Plastic Headlight Lenses

You have to wash the car first. Whether you're waxing or polishing (in case you don't understand, waxing is the act of filling and coating, while polishing is the use of any degree of abrasive), any substances on the surface that you didn't invite will scratch while you rub. And don't be afraid to wipe down surfaces like the plastic lens with a detailer between attacks, to keep invading substances to a minimum. We've also found automotive clay bar treatments effective on plastic, so you may run clay over the lens too—it's very effective at removing extra-stuck surface contamination.

Rub with More Grit
Our second plastic-bufftastic attack involved a more assertive polish, using a product we will not name since its maker's intended purpose does not include plastics. That said, if you talk to the folks who created the medium and exert due diligence, whether or not a polish is plastic-friendly will be readily evident. Always test the polish on a small portion of the lens anyway, just to make sure. With this second polish, a little more spark came to the clear plastic, but the nicks and dings left by the first polish used were still there. What next?


A little garage brainstorming led us to our third and final approach: add heat. It's not about whipping out a torch here, but the introduction of a small amount of warmth that could minutely soften the edges of nicks in the plastic, which are the part of the nick you see. Wear down the edges in a scratch and the scratch virtually disappears. It's the same principal employed when polishing car paint, as you want to eliminate the grabby visual cue in the scratch—its edges. Anyway, we whipped out the power wheel and went to town, slowly. A few RPM at a time, a little pressure at a time (never leaning into the buffer, as that's instant death for plastic or paint) and a good dose of the mildest plastic polish—and the remaining marks in the clear lens plastic began to fade. This is good. We are paranoid as to the overall peril to the plastic posed by an aggressive device like the buffer, though, so we did only a small bit of work with it before putting the device down for the afternoon. Without perfect light and surplus patience, this method could turn on us in a hurry, so it's back for a few minutes tomorrow when we're reassured the wheel is golden. This time we used a foam disc, too, so perhaps it's a cotton pad tomorrow.


Remember, sometimes your lenses are just beyond saving. Plastics are affected by ultraviolet and environmental eradication, and their resilience is thusly decreased, opening them up to suffer more damage from the same abuse. Even the best-maintained covers will eventually wear out. If you've been caring for them from the get-go, it'll take longer than you'll own the vehicle, but some plastics don't last. Pitting, fading that goes deeper than the surface, yellowing, or cracked, brittle plastic all signal it's time for new plastic. You just might not be able to fix them this time, but you can make a good effort with the tricks here.