Headlight Restoration: 600–3000 Grit Wet Sand & UV Seal

Cloudy, yellowed headlights make night driving harder and your car look older than it is. The fix isn’t magic gel—it’s a clean, controlled wet-sanding process that removes oxidized polycarbonate, tightens the scratch field step by step, and then locks in clarity with a UV-protective sealant. This guide gives you a simple, repeatable workflow using a three-grit ladder—600 → 1000 → 3000 (all wet)—so you get long-lasting clarity without power tools or guesswork.

Why Sanding Matters

Most modern headlight lenses are polycarbonate with a thin factory UV coating. Sun and road wear degrade that coating, turning the surface porous and hazy. If you only apply a polish, you’ll temporarily fill scratches and oxidation, but the haze returns quickly. A disciplined sand-and-seal process (1) levels the damaged layer to a uniform plane, (2) refines scratches in predictable steps so the surface reads evenly, and (3) protects the plastic with a fresh UV barrier so clarity actually lasts.

Tools & Supplies

• Wet/dry silicon-carbide sandpaper sheets: 600, 1000, 3000.
• Firm mini hand block (1–3 in.) and a thin soft foam pad for curves.
• Spray bottle with clean water + a drop of dish soap (lubricant).
• Rubber squeegee to read the surface; clean microfiber towels.
• Masking tape and plastic to protect paint, trim, and rubber seals.
• UV headlight sealant/clear (wipe-on or two-part) and applicators.
• Panel wipe/isopropyl alcohol for final clean before sealing.
• PPE: nitrile gloves, eye protection; work in the shade.

Recommended Grit Sequence

• 600 grit (wet): Primary cut to remove the oxidized layer and stubborn scratches.
• 1000 grit (wet): Refinement to erase 600 tracks and even the field.
• 3000 grit (wet): Pre-polish sheen that minimizes time on compounds (often no compound needed if sealing).

Step-by-Step: Clear Lenses, Lasting Results

1. Wash, dry, and mask. Clean the lenses and surrounding paint/trim. Mask generously—water and slurry carry abrasive. Work out of direct sun so the surface stays cool and wet.
2. Check what you’re removing. If the lens has peeling clear or deep pits, plan on spending a bit longer at the first grit and keep your block flat to avoid waves. Never chase defects with fingertip pressure.
3. Level at 600 (wet). Flood the lens with soapy water. Wrap a fresh sheet of 600 Grit (25-pack) around a firm mini block and sand with feather-light, overlapping strokes. Squeegee every minute to read progress. Your goal is to turn the surface into a uniform, dull satin—no shiny islands. Rotate to a fresh section the moment cut slows.
4. Refine at 1000 (wet). Rinse thoroughly, then slightly change your stroke direction (finish horizontal if you started vertical). Replace every 600 line with a tighter, even field using 1000 Grit (50-pack). Keep pressure light and the block flat through curves—use a thin foam pad only where the lens bends strongly.
5. Pre-polish at 3000 (wet). Rinse again and move to 3000 Grit (100-pack). You’re tightening the field to a uniform, fine haze. After a few passes and a squeegee check, the lens should look evenly dull-bright with no visible 1000 tracks.
6. Clean and dehydrate. Rinse, dry with clean microfibers, and wipe with panel wipe/isopropyl to remove residues. Let the lens air-dry fully—no trapped water before sealing.
7. Apply UV sealant. Follow the product’s instructions. Most wipe-on systems want a thin, even coat applied in one direction, then left to cure. Two-part clear kits may require mixing and a longer set time. Work dust-free; one stray fiber will telegraph.
8. Optional quick polish (before sealing). If you want extra pop, a brief pass with a finishing compound on a soft pad can brighten the 3000 haze. Keep RPM low and pads clean; stop as soon as the lens clears, then degrease and seal.
9. Cure and inspect. Let the UV coating cure as directed. Remove masking, clean edges, and check clarity from multiple angles. Repeat the last grit locally if you missed a patch, then re-seal that area.

Special Cases

Severe peeling/etching: Spend more time at 600 and make sure every shiny island is gone before you climb. If pits remain after a uniform cut, accept a minimal halo rather than over-thinning the lens.
Complex curves: Use a thin foam interface to maintain contact without printing flats; keep the block moving.
Glass headlights: Rare on modern cars; sanding glass requires diamond abrasives—don’t use this plastic-focused process.
Pre-tinted or protective films: Remove films before sanding; sanding over film ruins it and can gum paper.

Pro Tips

• Flat block = flat optics. Fingers create troughs that distort light. Always block on flats and use a thin foam pad only to follow curves.
• Read with a squeegee. Wipe the slurry often. Shiny dots = highs left; a uniform satin = done for that grit.
• Keep it wet and cool. Water floats swarf and prevents loading. If the sheet drags or blackens quickly, you need more lubrication or a fresh section.
• Crosshatch, then finish one way. A slight angle change at each grit reveals leftover scratches; finish each step with consistent, straight strokes.
• Seal the same day. Freshly leveled plastic re-oxidizes quickly. Degrease and apply UV clear/sealant right after sanding.

Aftercare

• Avoid washing or getting the lenses wet for the first 24 hours after sealing (or per label).
• Use pH-neutral soaps; avoid harsh chemicals on fresh coatings.
• Park in the shade when possible; UV exposure is cumulative.
• Refresh the wipe-on sealant annually (or as recommended) to maintain UV protection.

FAQs

• Can I start at 800 instead of 600? Yes—if the damage is mild. If shiny islands of oxidation remain at 800, drop briefly to 600 to clear them, then continue.
• Do I need compound after 3000? Not always. If you’re sealing, 3000 leaves a fine enough haze that the coating levels nicely. Compound only if you want maximum clarity before sealing.
• How long will it last? With a quality UV sealant and basic care, many see a year or more before a quick refresh is needed. Unsealed sanding will haze again quickly.
• Toothpaste hack? It’s a mild abrasive—results are temporary and lack UV protection. Use a proper grit ladder and sealant for lasting clarity.
• Machine vs hand? Hand blocking gives the flattest, safest control. If you use a small DA, keep speed low, pad flat, and finish by hand.

Watch & Learn

Closing: Lasting headlight clarity comes from process, not promises: 600 → 1000 → 3000 (all wet), then a proper UV seal. Keep the block flat, read with a squeegee, and seal the same day. Stock the exact sheets so you can stay disciplined at each step—reset oxidation quickly with 600 Grit (25-pack), refine fast with 1000 Grit (50-pack), and leave a uniform pre-polish sheen with 3000 Grit (100-pack). Do that, and the haze won’t be back any time soon.