Washing windows is a tricky business. You think you've got them cleaned and then the sun starts shining through showing you all the streaky mess you've left. If this has happened to you, then you should read the following tips.
If you've ever hired professional window washers you may have noticed that they didn't pull out their Windex and paper towels to get the job done, and neither should you. The most effective window washing equipment is a squeegee with a 10 to 14 inch blade. They can be bought from a janitorial supply store. You will also need a sponge and a cloth. Rather than store bought glass cleaner, try the following solution: Dilute ½ cup ammonia and ½ cup white vinegar with a gallon of warm water. Once you've got the right equipment, a successful job is all in the technique. First, apply the solution to the window with the sponge, scrubbing where there is caked on dirt. Then, wipe the blade of the squeegee with a damp cloth as it will slide better on glass. Hold the squeegee at an angle and drag it across the glass, either side to side or from top to bottom. You should wipe the blade with the cloth after each swipe.
Once you have used the squeegee on the whole window, wipe the sill with the cloth to remove excess water. Do not wipe drops of water that may accumulate at the edge of the window. If you do, they will smear, if left alone, they will simply dry.
Here are some more helpful hints:
Never wash windows in the bright sunlight. This will make them dry to fast and leave a residue that results in streaking
To make windows shine, rub them with a clean blackboard eraser after cleaning.
If you have large windows to clean sponge and the squeegee only half at a time, beginning with the top half.