A sunray-oxidized plastic headlight lens is common on older vehicles and those left outside continuously. The degree of oxidation can vary from a slight film to a heavy uneven one. Mine was crusty and thick, and was turning yellow in places. I could not see the headlight bulb behind the otherwise clear lens. Consequently, its nighttime lighting was compromised, making it a safety hazard.
Replacing this lens is costly, around $200. It was much cheaper and easier to fix it myself with a $10 restoring kit and a rotary tool. Here is how.
Store-bought restoration kit used ($10 or less)
- 4-oz of thick burnishing fluid
- 4-oz of spray lubricant (treated water)
- 3 burnishing pads (2″x2″-square) of differing fine grits
- 1 sealed-in liquid wax wipe
- 1 thin plastic glove
Additional items used
- a roll of one-inch-wide masking tape
- sturdy rubber gloves
- application rag
- wiping cloth or towel
- safety glasses or goggles (splattering occurs)
- circulating fan, if done indoors
- 1 handheld rotary device (Dremel-type), 5000-rpm or less
- 1 rotary polishing attachment with 2 rotary felt buffering pads attached to its stem (the pads are 1/4″-thick wheels, 1″ in diameter, each)
Warning! This high-speed burnishing step must be done with a very light/soft touch, else it will melt or burn-scar the lens’ plastic surface. Keep the outer rolling surface of the felt pads flat against the lens when they touch it. Or, if you think it cannot be done this way, use a hand-drill buffing attachment (1500-rpm) instead, or do it by hand.
- Clean the headlight surface.
- Mask tape any painted metal edges around it.
- Put on the rubber gloves.
- With a small rag, apply a the thick burnishing fluid over the cloudy part of the lens.
- With the rotary tool set at its slowest speed (#1), lightly burnish the clouded part of the lens with steady adjacent back-and-forth strokes. Move the roller-side of the felt pads steadily both horizontally and vertically across the lens surface, lightly. Tip: Take your time. This method is much faster than doing it by hand.
- To keep the thick liquid moist, spray it occasionally with the lubricant.
- After 2-3 full swipes over the clouded area, wipe the lens clean with a large rag or towel. Check the progress.
- As needed, repeat steps 4 through 7 until the lens is restored enough to pass its head-lighting safely. Tip: Quit while you are ahead. Try not to make the lens look brand new again. Tiny amounts of cloudiness might still remain when the basic restoration is done.
- Rinse and wipe the lens clean.
- Apply two coats of liquid wax to it, and let dry for 24-hours.
The soft half-inch-thick turning surface of the felt pads is small compared to the wider surfaces of the hand-drill buffing attachment or the handheld scrubbing pads. However, its speed makes up for it by effectively removing the oxidation film little bit at a time.
Also, the finely engineered burnishing fluid from a commercial kit is probably the best kind to use with a high-speed rotary device. I can now see my headlight bulb in its well behind the restored lens just fine. For more information on restoring headlight surfaces, see this website.