Use a garden hose, soft bristled brush and a Mr. Clean Autodry car wash kit. This kit comprises of a spray nozzle selector, liquid soap and a water filter. Install the water filter, add soap and attach the unit to the end of the garden hose. The selector switch allows you to spray plain water, soap, or filtered water.
Rinse the windows with plain unfiltered water.
Select the soap spray setting and clean the windows with a soft bristled brush. Do not use any other soap than provided by the car wash kit. Dish soap will clog the unit and not cause the water to sheet off the glass properly.
Rinse the windows again with plain unfiltered water.
Select the filtered water setting. The spray will be light but if you start from the top of the window, the water will sheet off the glass. The filter is designed to remove minerals from the water so water spots are not a problem when the window dries.
Allow the windows to air dry. You should have sparkling windows without having to squeegee.