General wear from the elements can make your windshield dirtier than you might think. Mineral deposits, road oils, pollution and a variety of other agents can leave your glass windshield feeling gritty and rough. In these cases, an ordinary glass cleaner will not suffice. You will need to polish your windshield.
Assess the current state of your windshield. Windshields that are grittier or scratched will likely need a machine polisher to return them to their "good as new" state, while mildly damaged windshields may be able to be polished sufficiently with a little elbow grease.
Purchase a glass polishing agent made specifically for windshields. These products can be found at some auto supply and hardware retailers.
Buy or rent a machine polisher if indicated by the condition of your windshield and/or the polishing product you choose. These can also be found at hardware stores, as orbital polishers have a variety of functions beyond auto detailing. Purchase at least one glass polishing disk to go along with your machine polisher.
Read the manufacturer's instructions that come with the glass polishing agent for proper application. Most polishers are applied in a circular pattern over the entire windshield, allowed to dry and then rinsed off with water.
Go over the windshield with a clean microfiber cloth to give it a final buffing and remove any residue there might be. The windshield should shine like new and be smooth to the touch when you are finished.
