Applying wax to your car's exterior will help keep the paint and exterior surfaces shiny and help prevent rust and other damage from exposure to the elements. Sometimes, however, wax winds up in places where it isn't meant to be, such as on glass. Removing car wax from a windshield isn't difficult, but you have to be careful about how it's done so you don't scratch the glass. There are a few different methods you can try to see which best does the job for you.
Apply rubbing alcohol to a clean, lint-free cloth. Rub the cloth on the wax spots on the windshield. Make several passes with the rag until the wax starts to dissolve.
Spray a commercial degreaser on the wax you want to remove from the windshield. Wait for a minute or so and wipe off the wax with a rag or cloth. One thing to keep in mind is that degreasers can be harmful to paint, so take care not to get any on the bonnet or roof.
Scrape away the wax with a toothbrush or toothpick. A little more labour intensive than some of the other methods, this will help ensure that you get rid of all the wax. Use a soft-bristled toothbrush on the windshield. If you're concerned about scratches, use the toothpick.
Clean the windshield with a standard glass cleaner and paper towels once you have removed the wax.