In order to remove wax from a car windshield, the best product to use is nail polish remover, or acetone, which should be applied with a cotton swab or paper towel. Give a windshield a final cleaning with a regular glass cleaner after removing wax with help from an auto mechanic in this free video on car maintenance.
How to remove wax from a car windshield. Generally the best way to remove most dirt from a car windshield is using a good quality glass cleaner, something like something specifically designed for vehicles with a foam type spray can be very efficient because it doesn't run down the glass it stays in place but any glass cleaner usually will work fine, you just spray it on and let it soak in for a little bit and then wipe it off and you can see that in this case this was a very dirty windshield but the glass cleaner takes it off very effectively. There are certain things, however, bug debris, road tar, wax, that do not want to come off easily from a windshield and in that case what you can use is nail polish remover which is essentially acetone and what you want to do is apply the acetone to either a cotton swab or a piece of paper towel and you can work it directly into the area that has the either wax or bug tar or bug bodies or road tar or the like and the acetone will break the lax down or the tar down and then once you are done cleaning with the acetone you want to give it one final cleaning with standard window cleaner and then you should have a nice clean windshield.