Fill a spray bottle with a 1 to 1 mixture of plain ammonia and water. Lightly mist one side of a lint-free cloth. If you use too much liquid and soak the cloth, you will fight streaks. Wipe the glass in a circular motion to polish the glass. Wipe until the glass is dry, flipping the cloth as necessary to keep a clean side against the glass. This method works best if the window is not terribly dirty and only needs a light touch-up for spots or smears.
Wash Exteriors With a Squeegee
Windows become dirtier outside than inside, so the the exteriors require different methods. Add 3 drops of dishwashing liquid to a gallon of water and mix it well. Wash the glass with soapy water, using a soft sponge. Immediately drag a squeegee horizontally across the top of the glass, creating a clean space. Wipe the squeegee clean with a rag. Working from the clean space, drag the squeegee down the glass at an angle. Wipe any streaks or drips with a clean rag before they have a chance to dry. Soapy water dries fast in direct sunlight, which doubles the work of window washing. Wait until the sun is not shining directly on the glass to begin cleaning your windows.
Use Newspapers and Water
Use a soft brush to clear away debris from the window frame to prevent muddy trails down the frame and to help keep dirt from pulling up onto the window as you clean. Using too much cleaner is unnecessary and expensive. Sometimes you don't need cleaner at all. Plain water and a newspaper tidy up everyday smudges on windows. Lightly mist a sheet of newspaper and polish the glass in a circular motion until it is dry.
Scrub Heavily Soiled Windows
If the exterior of a window is excessively dirty, as often happens during pollen season or after a thunderstorm, rinse the window using a garden hose first to remove excess dirt and grime that could scratch the glass. Lightly scrub the glass with a soft sponge saturated in dishwashing detergent and water. Rinse the window with a garden hose before the detergent has a chance to dry. Squeegee across the glass and then polish with a lint-free cloth or newspaper until it is completely dry.
Pre-Treat Special Problems
Clean problem areas, like old bird droppings and tree sap, before washing the window. Lightly scrub bird droppings with a soft brush and soapy water. Clean tree sap with a glass-safe solvent and a clean rag. Wipe away residue with a rag before washing the whole window. Cleaning stubborn problems like these first keeps the mess from pulling across the glass and reduces the chances of spotting and streaking.