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If you have a larger budget, consider purchasing an automotive glass cleaner. These cleaners are more expensive but will generally give you better results. Standard glass cleaners such as Windex or a foaming glass cleaner such as ZEP will also work well. Finally, some people create their own cleaners by using a water and vinegar mixture or simply rubbing pure ammonia on their windshield. Ammonia is an excellent glass cleaner. However, it can easily damage the paint, upholstery, and carpet in your car. Be careful of drips when using it as a cleaner. To make your own water-vinegar cleaner, mix one part hot water with one part vinegar in a spray bottle. Shake well. First, mist a thin layer of the cleaner onto the windshield. If you can't reach your entire windshield at once just clean half of it at a time. Using a new, clean microfiber towel, wipe the windshield clean in a horizontal back and forth motion. Gently lift the windshield wipers out from the car to clean the glass underneath them. If you're using ammonia to clean your windows, pour a small amount of ammonia on the microfiber cloth before wiping the windshield. Remember to wear gloves when handling ammonia. If you don't have microfiber cloths, newspaper can be used instead. If you don't have microfiber towels consider using a squeegee instead. Mist a thin layer of your cleaner on your windshield. Use the spongy side of the squeegee to scrub the dirt and grease off your windshield. Once the entire window is soapy, turn the squeegee over. Run the rubbery part of the squeegee across the glass in sections, pressing gently to remove all of the soapy liquid. When using a squeegee, you can skip the cleaner and fill a bucket with dish soap and warm water. Dip the squeegee in the bucket and clean the windows. Keep a paper towel on hand to dry the rubber side of the squeegee in between strokes. Use a fresh, clean microfiber cloth. If you use a dirty or washed cloth you risk scratching the glass of your windshield. Dry the glass using smooth, circular motions. Press gently into the glass as you wipe to remove any stubborn dirt particles on the glass. Work in small sections but work quickly; if the cleaning fluid dries on its own it can leave fresh streaks. If you don't have microfiber cloths, consider buffing the windshield dry with newspaper. The newsprint won't leave lint marks and the ink polishes the windows to a shine. Don't let the windshield dry on this own. This is how those pesky streaks are created in the first place. Move to the inside of the car and repeat the cleaning process on the inside of the car. First, lightly mist the glass with cleaner and gently clean the surface with a fresh microfiber towel. Next, dry the glass with a circular motion and inspect the surface for streaks. Repeat the process if necessary. Keep all the doors open to ventilate your workspace, especially if you're using ammonia. Breathing in chemical fumes can be harmful to your health. Don't use a squeegee on the inside of your car. Windshield wipers alone can't wipe away muddy debris from your windshield. This debris can dangerously limit your vision while you drive. Make sure you read your car manufacturers manual and know how to spray wiper fluid onto your windshield while driving. Most cars have a lever near the steering wheel that operates the windshield wipers. To spray windshield wiper fluid, simply pull the lever towards you. Check your car periodically to make sure your wiper fluid is at the right level. Never substitute with water.

Summary:
Choose a glass cleaner. Wash your windshield. Wash your windshield with a squeegee. Dry the windshield. Clean the inside of the windshield. Use wiper fluid when driving.