Short answer: streaks appear because an ordinary cloth or sponge moves the dirty water around the glass instead of absorbing it. A microfibre cloth grabs hold of moisture and dirt and keeps hold of it. Clean the window lightly damp and let it dry: there is no need to buff afterwards and you need no cleaning product.
You have just done your windows. The sun comes through and you see smears everywhere. Familiar, and frustrating. Below you can read where those streaks come from and how to prevent them for good.
Why does my window leave streaks after cleaning?
It is not down to your technique
Streaks are almost never the fault of the person doing the cleaning. They come from the material in your hand.
A cotton cloth, a sponge or an old tea towel pushes water and dirt across the surface. Part of it stays behind, dries up, and that is what you see as smears. Cleaning product plays a part as well: soap residue dries into a thin haze.
A microfibre cloth works differently. The yarn is spun into thousands of tiny hooks that grab hold of moisture and dirt and carry them into the cloth. What goes in only comes out when you rinse it.
What makes a good window cloth different from an ordinary cloth?
Three things make the difference
- Holding on instead of moving around. The fibres pull moisture, dust and grease inwards and do not let go.
- Absorbency. The cloth takes up many times its own weight, so you wring it out far less often.
- A dense weave. That is why it keeps working, even after dozens of washes.
These properties are built into the iZi-Clean Wonder Cloths, the cloths most customers use on their windows. If you want to see the whole range first, take a look at the Wonder Cloths.
How do I get my windows streak-free?
You need nothing more than a cloth and water. Here is how it goes in four steps:
- Make the cloth lightly damp with water. Water only, no cleaning product. Squeeze it out well: it should feel damp, not wet.
- Wipe the glass. Work from top to bottom, so you do not make a clean part dirty again.
- Let it dry. The little moisture left behind evaporates on its own, without any haze.
- Want it finished extra fast? Then go over it with a dry cloth. For larger surfaces and the bathroom the iZi-Dry drying cloth works well for that.
You will find more explanation with photos on the page streak-free window cleaning.
What else can I use the same cloth for?
Anything smooth and shiny
- Mirrors: toothpaste splashes and fingerprints gone, without any haze.
- High-gloss kitchen cabinets: grease and cooking vapor off.
- Stainless steel: taps and appliances shiny, without any lint.
- Chrome in the bathroom: showerhead and towel rail clear again.
How do I keep the cloth good for years?
Microfibre lasts a long time, provided you leave two things alone:
- No fabric softener. It lays a film around the fibres, so they no longer absorb moisture.
- Not in the dryer. High heat damages the fibres.
Wash them at 40 degrees at most and hang them to dry. Then you will still be taking the same cloth out of the cupboard years from now.
Frequently asked questions about window cleaning
Do I really not need any glass cleaner?
No. Cleaning product actually leaves soap residue behind that dries into streaks. Water is enough.
May the cloth be wet?
Lightly damp works best. Too wet means water is left standing on the glass and that can still leave smears.
When is the best time to do my windows?
Not in full sun. The water then dries faster than you can wipe. On a cloudy day or in the shade it goes more easily.
How often do I have to wash the cloth?
Rinse it out under the tap after use. As soon as it absorbs less well, it goes in the machine at 40 degrees, without fabric softener.
Does this work on my car windows too?
Yes. Car windows come out clear as well, on the inside just as much as on the outside.
More questions? Take a look at the frequently asked questions or send us a message.