Window washing secret Number 1: to a bucket of warm water, add 1 tablespoon of liquid dishwashing detergent.
Secret Number 2: apply the cleaning solution with a scrubber sleeve. You’ll find these in almost any hardware store or home improvement center. They come with a frame like this, just slip it over.. Lay the scrubber sleeve flat on the glass. Using a circular or back and forth motion, apply the cleaning solution to the window.
Secret Number 3: remove the cleaning solution with a professional quality Squeegee, one that looks like this. Tip the Squeegee up so that only a couple of inches are touching the glass. Then remove the strip of water at the top of the window. Professionals call this, “cutting an edge”. Dry off the Squeegee. Place it in the dry strip at the top of the window, and remove the solution by moving from top to bottom. At the end of each stroke, dry off the Squeegee, and then put it back in the dry strip at the top and repeat the process. Perhaps the most important thing to remember about cleaning windows this way, is always put a dry Squeegee on dry glass.
With a little practice, you can clean a window in this size in less than a minute.