Streak free methods. Try to choose an overcast day for washing windows. Or do the job when the sun is not shining directly onto the glass. Sun causes streaks.
Some window washers recommend cleaning with clear, tepid water. If windows are very dirty, you may prefer a cleaner. Use a commercial type or make your own, less expensive, version by mixing 2 tablespoons household ammonia or white vinegar with 1 quart of warm water. If temperatures are below freezing, add 1/4 cup denatured alcohol or 1 tablespoon glycerine to keep the cleaner from freezing.
Put the solution or water into a spray bottle or apply it with a sponge or a rag wrung out thoroughly to avoid drips. Start at the top of a window. If there are many panes, complete a horizontal row at a time. Use a toothbrush or cotton swab to get dirt out of corners. If using a cleaning solution, rinse.
Dry the window with paper towels, crumpled newspaper, a chamois, or a lint-free rag. Wipe one side of the glass with horizontal strokes, the other vertically; if you leave streaks, you’ll know on which side. Remove streaks with a soft, dry cloth.