Tempered glass is treated to withstand force, so it will not break easily. Manufacturers often temper glass if it is intended for use as doors or railings. In most cases, shower glass doors are tempered. Take special care of your glass shower doors to ensure that you don't scratch them. Clean them often, especially if you have hard water or soap scum buildup.
Mix 1 cup rubbing alcohol with 1 cup water and 1 tbsp. vinegar.
Pour the solution into a spray bottle.
Spray the solution on the tempered glass shower doors.
Wipe off the solution with paper towels. The sprayed mixture will remove hard water stains and soap scum.