You have just done the windows, the sun comes round, and there are smears everywhere. That is rarely down to your technique. Below you will find where streaks really come from, what vinegar, methylated spirits and newspaper actually do, and which method is left standing.
Short answer
Streaks are not dirt. They are what your cleaning product leaves behind.
Almost every product leaves something on the glass: soap residue, minerals from the tap water, or a thin layer of shine that dries into a haze. Leave the product out and clean with a tightly woven microfibre cloth and water alone, and nothing is left on the glass to dry. No residue, no streak.
Why do you get streaks on your windows?
Because something is left on the glass that then dries: soap, limescale from the tap water, or fibres from your cloth.
Glass is smooth and dense. Dirt barely clings to it, which is why it takes so little to get it clean. The problem sits in the last step: the drying. Anything still on the pane at that moment shows itself the second the water evaporates.
Three culprits keep coming back. Soap residue you never quite get off. Limescale from hard tap water, which stays behind as a white veil. And lint from a cotton cloth, an old tea towel or a sheet of kitchen roll.
There is another reason a sponge or a tea towel works against you. Those materials do not take the dirty water up, they shove it along in front of them. Part of it stays behind, dries, and an hour later you see it again as smears.
The home remedies measured up
They all work a bit, and they all have the same problem: they leave something behind.
| Remedy | What it does | Where it goes wrong |
|---|---|---|
| Vinegar | A mild acid that dissolves limescale | Leaves a film you have to rinse off, and the smell is sharp |
| Methylated spirits | Evaporates fast and cuts through grease | Flammable, gives off fumes in a small room, and is overkill for ordinary dust |
| Newspaper | Absorbs and polishes a little | Modern ink comes off on your frames and your hands; the old trick dates from a different ink |
| Washing-up liquid | Loosens grease | Leaves a soapy layer that actually attracts dust |
| Glass cleaner with added shine | Gives an instant gleam | The shine agent sits there as a wafer-thin layer and pulls dust back within a few days |
| Squeegee | Pulls the water off in strips | Only works once you have the knack, and water always sits along the edges |
Spot the pattern? Every product dissolves something, but adds something of its own that you then have to get off again. That last little step is exactly where the streaks come from.
With glass cleaner there is a sting in the tail. That layer of shine looks lovely on day one, but it works like a magnet on dust. So you are back at the window sooner than you need to be, thinking your glass gets dirty quickly when the product is the reason.
Do not use vinegar on natural stone
Have you got marble, limestone or travertine around your windows or in the bathroom? Vinegar is an acid and it attacks those stones. You end up with dull patches you cannot get out again. Water is always the safe choice there.
The method that is left standing
If the problem is that products leave something behind, the answer is simple: leave the product out.
A tightly woven microfibre cloth picks dirt up mechanically instead of loosening it chemically. The fibres are split on a microscopic scale, like a cake sliced into countless slivers. Between those slivers a capillary action builds up that does two things at once: the dirt is drawn deep into the wedge-shaped openings, and the bond between dirt and glass is broken. That is why even fingerprints come away without effort.
You get the cloth just damp, you clean, and nothing is left on the glass to dry.
No bottle, no rinsing off, no waiting. Just water and the cloth, and then that pane you look straight through.
How to clean your windows streak-free in four steps
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1
Pick a cloudy day or work in the shade
In full sun the water dries faster than you can clean. Then you get streaks, however good your cloth is.
-
2
Get the cloth just damp, not wet
Wring it out until it stops dripping. Too much water works against you, because a pool is left on the glass that dries into rings anyway.
-
3
Work in strips from top to bottom
That way you know where you have been, you do not drag drips over glass you have finished, and you spot straight away if you have missed a patch.
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4
Go over it again with a dry side
Fold the cloth round to a dry face and go over the glass once more. That is the step that makes it truly invisible.
One more thing plenty of people overlook: swap cloths as soon as one is saturated with dirt or moisture. Carrying on with a full cloth is the single most common cause of streaks among people who otherwise do everything right. Which is why it pays to keep a stack of clean cloths to hand rather than just the one.
Does this work on mirrors and the shower screen too?
Yes, and that is where you see the difference fastest. Anything that shines or reflects asks for the same fibre and the same method.
A glass shower door is the strictest test there is: every smear lights up the moment the light hits it. That is precisely where most people first notice what a dense fibre does. Same cloth, just damp, no product.
- Mirrors: toothpaste splashes and fingerprints gone, with no haze.
- Screens and tablets: clean in seconds, with no risk of scratching.
- High-gloss kitchen units: grease and cooking steam off, shine back.
- Stainless steel and chrome: taps, appliances and the shower head clear again, with no lint.
- Glassware and display cabinets: crystal clear instead of cloudy.
- Car windows: just as good on the inside as on the outside.
For mirrors we have written the method out step by step on the page about cleaning mirrors without streaks. If you would rather see it surface by surface, have a look at streak-free window cleaning.
What do you do with a brand new cloth?
Soak it for 15 minutes in lukewarm water and rinse it out well. After that it works at full strength straight away.
A little patience the first time pays off. Skip that step and the cloth takes up less moisture than it can for the first few uses, and on glass you notice that immediately.
After that the care is simple, and it decides whether your cloth lasts for years or starts shedding after a few months. Loose fibres from a worn cloth are themselves a cause of streaks.
Wash the cloths at 40 degrees, either on their own or with the same colours.
No fabric softener and no bleach. Softener lays a greasy film around the fibres, so they stop taking up moisture.
Not in the tumble dryer. High heat damages the fibres. Line drying is all it takes.
Washing with iZi-Wash Sheets leaves no residue in the fibres. If you are unsure about a washing instruction, have a look at our frequently asked questions.
When do you reach for a drying towel?
When the surface is genuinely wet, say a shower screen after a shower or a window with condensation on it.
You use the Wonder Cloth just damp for cleaning: it takes up to 7 times its own weight in moisture and removes 99.9% of bacteria with water alone. If it is wetter than that, the Drying Towel is the handier one. You use that one dry and it soaks up to 800 ml, so a whole shower screen is clear in a couple of passes. There is more on that in our article on the best drying towel for the bathroom.
Straight to the cloths
The sets people choose most often for windows and mirrors.
- iZi-Clean Wonder Cloth, 12 pack · the most popular value pack, three packs of four
- Starter pack, 4 cloths · to see it for yourself first
- Browse all Wonder Cloths
Frequently asked questions
Why do I get streaks on my windows?
Because something is left on the glass that then dries: soap residue, limescale from hard tap water, or lint from a cotton cloth. With no product and a tightly woven microfibre cloth, nothing is left behind to dry.
Can I clean my windows with water only?
Yes, and that is the whole idea. Dirt barely clings to glass, so a tightly woven microfibre cloth and water are enough. With no product, nothing is left behind that could give you streaks.
Can you clean windows with vinegar?
You can, because vinegar is a mild acid that dissolves limescale. But it leaves a film you have to rinse off, and the smell is sharp. You must not use it on natural stone, because the acid attacks the stone. With water alone you have none of those drawbacks.
Does the newspaper trick still work?
Less well than it used to. That tip comes from the days of a different printing ink. Modern ink comes off on your frames and your hands, and the newspaper itself leaves fibres behind.
Why do my windows get dirty again faster after glass cleaner?
Glass cleaners with fragrance or added shine leave a wafer-thin layer behind. It looks clean at first, but it attracts dust like a magnet. Within a few days you are cleaning them all over again.
How do you clean windows streak-free without a squeegee?
With a just damp microfibre cloth, in strips from top to bottom, and then go over it again with a dry side of the same cloth. A squeegee is not needed, and it tends to leave water sitting along the edges.
When is the best time to clean your windows?
On a cloudy day or in the shade. In full sun the water dries faster than you can clean, and you get streaks anyway.
Should the cloth be wet or just damp?
Just damp works best. Wring it out until it stops dripping. Too wet means water sits on the glass, and that can still leave rings.
Do I need to prepare a new cloth first?
Yes. Soak it for 15 minutes in lukewarm water and rinse it out well. After that it takes up moisture at full strength straight away.
Why does my old microfibre cloth leave streaks?
Loosely woven cloths start shedding after a number of washes. Those loose fibres stay behind on the glass and you see them again as smears. Fabric softener speeds that up, because it lays a film around the fibres.
Can I use the same cloth for mirrors, screens and car windows?
Yes. Mirrors, glass shower doors, screens, high-gloss kitchens, stainless steel, chrome, display cabinets and car windows all take the same fibre and the same method: just damp and with no product.
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