A car's windshield is subject to etching, pitting, scratches and hazing from the debris flying through the air, especially on freeways. Since replacing the entire windshield can be costly, repair scratches with glass polishing kits that are readily available in automotive stores. The kit provides the essential tools to repair the glass. The polishing compound included in the kit is the key ingredient in buffing out scratches. However, the polish will not remove cracks, and it is best to replace the windshield in such cases.
Clean the windshield with soap and water to remove any excess debris. Dry off with a rag.
Tape off the damaged area with masking tape to prevent any unwanted spills to surrounding areas.
Mix the polish with water according to the manufacturer's directions.
Spread the polish on the damaged area with a plastic knife provided in the kit. Skim off excess polish with the knife.
Attach a buffing component to a drill and operate the drill at a low speed to buff away the polish. Buff the polish until the scratches disappear. Overbuffing or buffing at high speeds may further damage the surface, so moderately buff the polish to remove scratches.
Apply glass treatment to protect against damage from snow, mud and water.
When mixing the polishing compound with water, use distilled water to avoid contamination from pollutants found in tap water. Practice on a scrap piece of glass to achieve a smoother repair surface.
If the nail catches when it runs across the glass, seek professional service. Such scratches may be too deep for repair with a polishing kit. Wear protective gloves when working with the polish to prevent any possible skin irritation. Work out of direct sunlight for best results.