Direct sunlight can cause your cleaner to dry and evaporate before you can properly wash it away, leading to streaks that are tough to buff out. Overcast skies also reduce glare on the glass, making streaks easier to find.
Clean the frame first
A lot of grime can hide in the window tracks and frame, and when mixed with window cleaner, it may form an unsightly sludge that can drip onto the glass while cleaning. To remove the grit, use a toothbrush and a sprinkle of baking soda and vinegar to scrub inside the tracks, then wipe away any remaining residue with a wet rag.
Make your own soap
Skip the specialty products and make your own cleaning solution using a mix of water and dish soap, which is tough enough to cut through grime on especially dirty windows, like those in the kitchen, yet won’t leave a residue. Alternatively, vinegar can also be used as an effective cleaner.
Paper is bad news
Paper towels and newspapers are commonly misused as products for scrubbing and drying the glass—but they just break down and leave lint behind. Use a microfiber cloth to do the job instead; it will grab dirt and dust and leave nothing behind.
Invest in a squeegee
The best way to ensure a streak-free shine is to make sure all the water and soap are removed from the window. Use a rubber-bladed squeegee tool to run over the glass from top to bottom to scrape away excess water.
Reach the top with a mop
For high exterior windows, use a sponge mop on a pole to clean with soapy water. Rinse the washed windows with a hose, and use a dry mop or a squeegee fastened to an adjustable pole to remove the water and prevent water spots from drying to the glass surface.