Windshield scratches, and which ones polish out
Most windshield scratches are wear from the wipers, and a fingernail tells you in a few seconds whether yours will polish out. Run it slowly across the mark. If it glides over, the damage is on the surface. If it catches or drops in, the scratch has cut into the glass.
Surface marks are the job our windshield buffing service is for, done at your address. The rest of this page helps you work out which kind you have.
Four kinds of mark on a windshield
- Fine haze across the wiper sweep
- A dull band that only shows when you drive towards a low sun or into oncoming headlights at night. Your fingernail slides over it. This is surface wear, and it is what windshield buffing is for.
- Arcs that follow the blade
- Thin curved lines in the shape of the wiper’s travel. Usually a worn blade or grit trapped under it. Light arcs polish out the same way as haze. If your nail catches in one, it has cut into the glass.
- A single deeper scratch
- A line you can feel, often from a stone dragged under a blade or something scraped across the glass. If your nail drops into it, polishing will not reach the bottom.
- A chip, a star or a crack
- Glass that is broken rather than worn. That needs a resin repair, which is a separate service with its own page.
For the last one, see windshield crack repair and what a crack repair can really fix.
Why deep scratches are left alone
Polishing glass works by taking a very thin layer off the surface around a mark until the mark stops showing. On a shallow scratch that layer is tiny. On a deep one, getting down to the bottom means removing a lot of glass in one spot, which leaves the glass thinner there and more likely to crack.
The area that matters most is the part the wipers sweep in front of the driver. A deep scratch there is a replacement question, and polishing is the wrong answer to it. We will say so before starting rather than after.
Where the scratches come from
- A worn wiper blade. Once the rubber edge tears, the hard part behind it scrapes the glass on every sweep.
- Wiping a dry, dusty windshield. The dust becomes the abrasive, which is why the washer fluid goes on before the wipers.
- Cleaning the glass with a scouring pad or a rough cloth.
- Paint polish used on glass. Its abrasive is a different grade from a glass polish and it can leave fine marks of its own.
Changing blades when they start to streak or chatter, and using the washer before the wipers, prevents most of it. Water marks are a separate problem with their own fix, covered on the windshield buffing page.
Book windshield buffing at your address
If your fingernail slides over the marks, read what our windshield buffing service covers and book it through the form. If you are not sure, describe the marks or send a photograph and we will tell you which job it is.
Sources
- NuVision Auto Glass, how to remove scratches from car glass: the fingernail test, worn wiper blades, deep scratches and thinner glass, paint polish on glass. nuvisionautoglass.com