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.
Hard water, which contains high levels of minerals like calcium and magnesium, can leave behind spots and streaks when it dries. If you're using tap water to clean your windows, these minerals can deposit on the glass, creating a hazy, smeared look. Pollutants and contaminants from the environment can also play a role.
First you completely rinse off the area to be cleaned. The next step is to apply the suds and let it sit for only 20 seconds, so it doesn't dry. The final step is to rinse it off working from top to bottom. Once it dries, it leaves a streak-free shine. Please check the manufacturers instructions for complete details.
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.
Plus, ammonia can leave streaks and film on some types of windows. But not to worry, CR found that the ammonia-free options cleaned just as well. The winner was Sprayway Foaming Glass Cleaner. It cut through all of CR's messes, leaving surfaces dry after just a single wipe.
So, why do your windows appear more grimy after they are cleaned? Cleaning your windows tends to reveal hard water stains, especially if they've been left untreated over the years. Here are the facts about hard water stains along with a few tips on how you can prevent them in the future.
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.
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.)
For best results, make sure you completely rinse suds. Do not allow product to dry before rinsing, rinse windows from top to bottom and use Windex® Outdoor Sprayer when the temperature is above 55º F. If the product is applied to eaves or siding above windows, it may drip down on windows.
There are many different formulations of Windex. The ingredients vary between products, but they typically contain surfactants, solvents, and dyes. These chemicals are irritating when swallowed and can cause unwanted signs and symptoms including vomiting and abdominal pain.
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.
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.
It's crucial to completely cleanse the glass after using a window cleaning solution. If you don't do this, the cleaning agent may dry on the surface and leave stains. To prevent this, remove the cleaning solution with a clean cloth or squeegee first, then wipe the surface completely dry with a lint-free cloth.
If you have smeared windows when you're finished cleaning, you've left cleaning solution, soap, or minerals behind. Whether you have white residue on windows or another blemish, the solution is the same. Clean faster, use cleaner water, and wipe away all your solution, so nothing is left behind.
To avoid streaks, it's important to clean the glass thoroughly before using Windex, and to use a clean, lint-free cloth to wipe the surface in a back-and-forth motion, rather than in circular motions that can trap streaks.
Use a soft brush or a sponge and remove dirt or cobwebs from the window surfaces. Mix equal parts white vinegar and water in a bucket. Add a few drops of dish soap to help cut through grease and grime. Use a hose with a sprayer attachment to wet the window thoroughly.
Mix equal parts white vinegar and distilled water in a spray bottle. Spray the solution onto the cloudy glass surface. Let it sit for a few minutes to loosen deposits. Wipe the glass with a microfiber cloth in circular motions.
Using Windex on your home windows might seem like a convenient choice, but it can leave residue behind and actually attract more dust. Instead invest in a squeegee and Dawn dish soap to clean windows. Start at the top and work your way down, using vertical or horizontal swoops.
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.
Pros: Effective Cleaning: Windex Original Glass Cleaner is known for its excellent cleaning power, leaving glass surfaces sparkling clean and streak-free. Versatility: Beyond glass, it can be used on multiple surfaces such as mirrors, chrome, stainless steel, and even some countertops.