A mixture of equal parts vinegar and water is a popular homemade window cleaner recipe; other homemade outdoor window cleaners feature ingredients such as lemon juice, baking soda, borax and corn starch. Toothpaste, peroxide and rubbing alcohol are also effective outdoor window cleaning aids. Homeowners may also make a very close approximation of Windex formula using ammonia and rubbing alcohol.
For very dirty windows, make the traditional vinegar and water recipe and add a half teaspoon of dish detergent. Use full strength vinegar on stubborn smudges. Borax and water solution is also an effective outdoor window cleaner; mix two tablespoons of borax with three cups of water, apply to windows and wipe clean. Substitute cornstarch if borax is unavailable. After cleaning windows with borax or cornstarch mixture, rinse the glass using a solution of equal parts vinegar and water
Baking soda makes an effective outdoor window cleaner; use two tablespoons per gallon of water. Mix a half cup of hydrogen peroxide into homemade window cleaning solution when cleaning outdoor windows with moldy trim or frames. Lemon juice and toothpaste make good homemade window polishes; wait for the windows to dry and polish scratched or dull areas with toothpaste or lemon juice and a soft cloth.
Mixing ammonia, rubbing alcohol and water creates the closest formula to commercial outdoor window cleaners, though it is not as safe as the vinegar or soda mixtures. Mix two cups of rubbing alcohol, four ounces of ammonia and a teaspoon of liquid dish soap in a gallon container; store any unused solution away from kids and pets. Do not allow the ammonia and alcohol solution to drip into flowerbeds while washing windows because it can kill plants.