A big problem is the evaporation rate. If you're cleaning your windows on a warm sunny day, the liquid part of the solution evaporates quickly and leaves behind a residue that appears as streaks. On the other hand, if you don't entirely remove the liquid you can also be left with a streaky window.
Choose lint-free
Microfiber or other lint-free towels won't leave behind little specks on glass surfaces. Newspaper or old, clean cotton diapers are other great options.
Those streaks are either dirt or some other gunk on the glass or they are the result of what you are using to wipe the Windex off with. I've cleaned some nasty windows in my life. When they're really dirty I use a rag with soapy water to wash the window first. Then once I have removed the gunk I go back with Windex.
It is critical to use a glass cleaner without additives like soaps, scents, or dyes, as these unnecessary additives cause streaks.. Start by spot cleaning any particularly difficult stains and grime. Next moderately apply glass cleaner to the whole surface—avoid using too much cleaner as that can lead to hazing.
And while ammonia-based cleaners like Windex are known for their cleaning power, the smell isn't so great. Plus, ammonia can leave streaks and film on some types of windows.
Too Much Soap in the Solution
Have you ever heard the phrase “too much of a good thing”? Well, window cleaner, this can absolutely apply to your soap solution. Your windows could be looking murky because you're using way too much of the good stuff.
One of our top picks for best window cleaner no streaks is the Amway Home Glass Cleaner. This product is streak-free and leaves a beautiful shine. It's also safe to use on all types of surfaces, including tinted windows.
Use a Squeegee for a Streak-Free Finish
Spray your cleaner on the glass and start at the top left corner. Ensuring the squeegee is flat against the glass, pull the squeegee down in a reverse S pattern. Wipe the blade clean, and repeat the process beginning at the top right corner.
Use Vinegar
Whether you are out of name brand glass cleaner or you want to use a more natural cleaner, vinegar works wonders on windows. Try a 50/50 solution of vinegar and water for a streak-free clean. You can use a spray bottle or dip a rag in the solution, just like you would an ordinary cleaner.
Best for Mirrors: Hope's Perfect Glass Cleaner
Mirrors with toothpaste splatter, fingerprints and smudges are no match for Hope's Perfect Glass Cleaner. The ammonia-free formula is safe for a variety of glass surfaces, including tinted windows, but we found it works best on mirrors.
Excessive Cleaning Solution
Whether you have purchased a premixed glass cleaner, or you are using your own soapy mixture, too much cleaning solution will cause streaky windows. It is a common misconception that the more cleaning solution you use, the cleaner the glass will be but with windows this is not the case.
Dish Soap Solution
Believe it or not, one of the most common and effective window cleaning solutions that is used by professionals is a mixture of dish soap and water. Simply mix one gallon of water with two teaspoons of liquid dish soap, and you have a professional window cleaning solution.
Streaks and smudges can form on your car windows for one of three reasons: you're not using enough cleaning product to cover these surfaces, you're using the wrong type of cleaner or you may be using the wrong type of microfiber cloth, a dirty microfiber or a paper towel to wipe down your windows and auto glass.
Paper towels are typically treated for absorbency, which makes them ideal for spills, but awful for glass cleaning. Instead, substitute your paper towels for something more practical, like actual cloth. Lint-free cotton cloths, like microfiber cloths are great options for glass cleaners.
This has to do with the evaporation rate—if your cleaning solution evaporates before you have time to wipe it off, it will leave a mark. Alcohol- and ammonia-based cleaners evaporate more quickly than vinegar, but any window cleaner can leave streaks if it isn't removed fast enough.
Create a solution of one part distilled vinegar and 10 parts warm water, then pour it into a spray bottle for easy use. Before you spray cleaning solution on the window, make sure to use a soft and clean microfiber cloth or paper towel to wipe away any excess dust or grime.
Add 1 tablespoon of Jet-Dry Rinse Aid to your cleaning solution. Add 2 tablespoons of Isopropyl (rubbing) alcohol to your cleaning water. Use a squeegee to dry the windows.
Your glass cleaner could be behind those pesky mirror streaks! Many commercial glass cleaners have cleaning agents like ammonia and detergent, which can end up streaking your mirror. So this means you cannot clean mirrors with Windex anymore? Not necessarily, but if you want to avoid streaks, less is better.
Even multi-purpose cleaners are too strong for cleaning mirrors. They often leave a toxic residue that makes mirrors hazy. Soapy cleaners also leave behind a residue that contributes to streaks, so avoid those too.
The top reasons why the glass and mirrors you clean are streaky typically boil down to these four things: Failure to pre-clean the surface. Ineffective cleaning solution. Ineffective tool.
Spray a stronger mix of 1:1 water and vinegar (or Windex, or glass cleaner) at your window, so that the solution covers most of the glass. (I found Windex to work better, but if you have pets—or kids—who frequently lick outdoor windows, vinegar may be the best route for you.)
Beat Evaporation to Banish Streaks
If the cleaner evaporates before you can wipe it away, it creates streaks. Spray your cleaner over small sections and wipe it away before moving on to avoid streaks if your cleaner is evaporating too fast.