How To Clean Windows Without Leaving Streaks – When cleaning windows it’s not always what you see is what you get! Some window cleaning chemicals won’t leave streaks right away but after a good drying period a dull film will start to appear. This usually occurs if the window cleaning solution has added chemicals that won’t evaporate and are left as a residue on the glass. When purchasing a good window cleaning chemical or solution it is usually best to purchase products that are ammonia based. Ammonia based products will evaporate quickly and not leave any residue. Concentrated glass cleaners are great for use in climates where the temperature changes, especially if you are using them outdoors. A concentrated glass cleaner can be diluted with the correct amount of water for the amount of moisture in the air and the ambient temperature. Mix in more water for hot and dry climates and less water for cooler moist climates. By using this method you can really cut down on those window streaks.