Use it as a temporary solution for a windshield crack
When your windshield suffers a rock chip while you’re traveling, you probably won’t have time to take your car to the garage right away. Still, you can’t let a cracked windshield without doing something about it because the damage may grow beyond repair. You can even end up needing a total windshield replacement if the crack spreads too far.
If the damage to the windshield isn’t severe, transparent nail polish can help you get by until you take your car to the workshop. You can put some packing tape on both sides of the glass to stop the cracks from getting worse and fill in the small holes and gaps with thin layers of polish. It isn’t a permanent fix, but it’ll let you travel safely.