We polish headlights clear, then protect them

Every headlight polish follows the same order

A headlight polish starts with a wash. Road film and bug residue sit on top of the lens, and polishing over grit drags it across the plastic and leaves fine scratches. Once the lens is clean and dry, we tape off the paint and trim around it. The pads and compounds that cut haze off a lens will also dull clear coat. The tape stays on until the last pass is done.

Then we look at how deep the damage goes. Light haze sits in the top of the worn coating and comes off with polish alone. Heavy yellowing, or a lens that feels rough under a fingertip, needs wet sanding first. The sanding starts coarse enough to cut off the dead layer, then steps finer until the whole lens looks evenly frosted. Skip a step in between and the scratches it should have removed show up as swirls when the lights are on.

Polish takes the frosted lens back to clear. On a good job, you can look straight through it to the reflector and the bulb. There is no cloudy ring left around the edges where the pad did not reach. The last step is a protective coat on the bare plastic. Sanding strips whatever factory protection was left, and a bare lens in the Tennessee sun yellows again much faster than it did the first time.

• Lens washed and dried before polishing starts
• Paint and trim taped off around each lamp
• Wet sanding when the yellowing runs deep
• Polished until you can see the bulb
• Protective coat on the finished lens

Tennessee sun turns plastic lenses yellow

Most cars on the road today have headlight lenses made of polycarbonate, a clear plastic that stands up to rocks far better than glass would. Sunlight breaks it down. Carmakers put a thin hard coat on the lens at the factory to slow that process. Once the coat wears through, the plastic under it oxidizes and turns yellow. You see it first as a dull film, then as a yellow cast that gets thicker every summer.

Middle Tennessee is hard on that coating. Summers are long and humid, and the sun stays high from late spring well into fall. A car parked on blacktop through a July afternoon bakes the lens for hours. Winter adds wear of its own, because brine and grit from treated roads get thrown against the front of the car on every wet drive. A car that lives outside yellows years ahead of the same model kept in a garage.

Where you park overnight makes a big difference. Around Nashville, a lot of families live in brick ranch houses with a carport or an open driveway. Older bungalows closer to town often have a short gravel drive or no drive at all, so the car stays parked on the street. Apartment and townhouse lots leave every car out in the open. Brentwood and Franklin subdivisions usually have garages, but the extra car still ends up in the driveway, and that is the one that yellows first.

Shortcuts make the yellow come back faster

Toothpaste and bug spray both get passed around as headlight fixes, and they do make a lens look better for a little while. Toothpaste is a mild abrasive, so it knocks off some of the loose surface. Bug spray softens the plastic and makes it look glossy. Neither one removes the dead layer, and neither leaves anything behind to protect the lens. The haze comes back fast, and the softened plastic often looks worse than before.

A real polish can go wrong too when steps get skipped. If the sanding stops at a coarse grit and jumps straight to polish, deep scratches stay in the lens and scatter the beam. A rushed final polish leaves a faint haze in the middle of the lens that you only notice at night. Leave out the protective coat, and the lens looks perfect on the day and starts to yellow again within a season.

Heat is the other thing a rushed job gets wrong. A polisher run too fast, or pressed hard in one spot, warms the plastic until it smears instead of cutting clean. That leaves a dull patch or a wavy spot that takes sanding to fix. On a hot afternoon with the lens already warm, it happens faster, so the work slows down and the pad keeps moving.

Cloudy lenses dim your headlights at night

A yellow lens costs you light at night. The haze scatters the beam before it reaches the road. Less light lands where you are looking, and more of it spills sideways as glare. On a dark back road outside town, that lost light can mean seeing a deer late instead of early. Rain makes it worse, because wet pavement reflects light away instead of back toward you.

After a polish, the change shows up the first time you drive after dark. The beam has a sharp top edge again instead of a soft smear. The road ahead looks brighter, and nobody had to aim the lights any higher. Both lamps should look the same from the front of the car. If one lens is clear and the other is still cloudy, the light on the road is uneven and the car looks lopsided.

Clear headlights also change how old a car looks. Yellow lenses are one of the first things people notice on a used car, and they can make an otherwise clean vehicle look worn out. On an older car, clear lenses go a long way toward making it look cared for. In her Google review of Everything Clean, Julie Sekrieh wrote: "They took an older model car and made it look brand new."

The work happens where you park

Everything Clean is a mobile detailer. We come to the car, at your home or at work, and do the polishing right where it is parked. Headlight work suits that well, because it only needs the car and some room at the front of it. The car never leaves the spot it is parked in. You do not have to find a ride or spend a morning in a shop waiting room.

The easiest setup is a driveway or a parking spot with open space in front of the bumper. A carport works well, and shade helps, because polish and coatings work better on a lens that is not hot to the touch. In an apartment or office lot, back into the space if you can, so the headlights face the open lane. Tell us about gate codes or parking rules when you book.

Headlights are often the last thing on a car that still looks old after a wash and detail. If you are also thinking about a full auto detail, mention the headlights when you ask for your free quote. When we finish, look at the lenses from a few steps back and then up close. They should be clear from edge to edge, with clean paint around them and no polish left in the seams.