How to Clean Car Windows Inside and Out (Without Streaks)

By Laura Pemberton · Updated on 8 October 2026

Short answer: clean the outside of your car windows after you wash the car, and the inside separately, because they collect different dirt. Outside it is road grime, rain spots and insects, which wash off. Inside it is a greasy film from the heater, the dashboard plastics and everyone's breath, which has to be lifted off with a dry microfibre cloth rather than spread around. Work on cool glass out of direct sun, use a little product on the cloth rather than the glass, and finish with a dry cloth. The inside of the windscreen is the hard part, and it is the part that matters most when the sun is low.

Why do the inside and the outside get dirty differently?

They face different problems, so they need different methods.

	Outside of the glass	Inside of the glass
What builds up	Road dust, traffic film, rain spots, insects, tree sap, winter salt	A thin greasy film, dust from the vents, fingerprints, dog nose prints
Where it comes from	The road and the weather	The heater, warm dashboard plastics, damp coats and breath
How you notice it	Visible dirt, wipers smearing	A grey haze and glare when the sun is low, or headlights at night
What removes it	Water, glass cleaner, a rinse	A dry or lightly dampened microfibre cloth, buffed dry
How often	Whenever you wash the car	Every few weeks, more often in autumn and winter

That inside film is real, not your imagination. As one Toyota Owners Club member [UK] put it, on newer cars it seems to come from "a mist of oil like substance that is given off by the plastics off gassing when the dash and surrounding plastics become hot". It is why a windscreen can look clean in the morning and smeary by the afternoon sun.

What do you need?

• Two or three clean microfibre cloths: one to clean, one to buff dry. Wash them without fabric conditioner, which leaves a residue that smears.
• A glass cleaner, or water with a splash of white vinegar. If your windows have an aftermarket tint film, check the label and avoid ammonia-based cleaners.
• For the inside of the windscreen, something with reach: a long-handled windscreen tool, or simply sitting in the passenger seat to get at the driver's side.

Kitchen roll, newspaper and old T-shirts tend to leave lint and streaks. As one PistonHeads member [UK] summed it up: "90% of the time there are smears left after cleaning it's the cloth used rather than the product."

How do you clean the outside of car windows?

1. Wash the car first, glass last. Otherwise dirty water from the roof runs straight back down the windows.
2. Work in the shade, on cool glass. Cleaner dries too fast on warm glass in the sun, and that is where streaks come from.
3. Lift the wipers and wipe the blades with a damp cloth, then clean the strip of glass they normally cover.
4. Spray, wipe, buff. Work top to bottom, one panel at a time, then buff with a dry cloth.
5. Don't forget the mirrors and the edges of each window that hide under the seals when the glass is up: wind each window down a few centimetres and clean the top edge.

How do you clean the inside of the windscreen without streaks?

1. Dust first. Wipe the top of the dashboard so you don't drag dust onto the glass.
2. Spray the cloth, not the glass. It keeps cleaner off the dashboard and stops runs at the bottom of the screen.
3. Start in the lower corners, where the glass meets the dashboard. They are the hardest to reach and the ones most people skip. Sit in the passenger seat for the driver's side, or use a long-handled tool.
4. Wipe in one direction inside and the other direction outside, for example side to side inside and up and down outside. If a streak appears, you will know which side it is on.
5. Buff dry with a clean cloth straight away.
6. Repeat for the side windows, rear screen and mirrors.

Which mistakes cause streaks?

• Cleaning in direct sun, or on glass still warm from the heater.
• Using too much product. More cleaner means more residue to wipe off.
• A cloth that is already dirty or damp, which just moves the film around.
• Wiping with your hand or sleeve when the screen mists up: the oil from your skin adds to the film you are trying to remove.
• Skipping the edges and the lower corners of the windscreen, where the film is thickest.

How often should you clean car windows?

Outside: whenever you wash the car, and more often in winter, when road salt and spray build up quickly. Inside: every few weeks, and more often from autumn onwards, when the heater runs and damp coats come into the car. One MoneySavingExpert member [UK] says of a newer car: "our new car needs doing at least once every 3 weeks otherwise night driving becomes a problem."

Clean glass also mists up far less than dirty glass. If misting and smears are your main problem, our guide on why your windscreen smears and mists up goes into the causes and the fastest way to clear it.

Is a windscreen cleaning tool worth it?

It depends on your car and on you. If you drive a small hatchback with a short dashboard, a microfibre cloth and the passenger seat trick will do. A long-handled tool earns its place when the windscreen slopes far away from you, the dashboard is deep, or reaching across is uncomfortable. One PistonHeads member [UK] described the problem well: "It does not help that it slopes away and the dash top is long and broad so getting a good, even hand pressure to clean is not easy."

Our GlassWand™ is one option, made for exactly this job. The facts:

• An aluminium handle that extends and locks, up to 25 inches (about 63 cm), and folds down to 8 inches (about 20 cm)
• A 6.5 inch head that pivots through 180°, so the cloth stays in contact with a curved windscreen right down to the dashboard
• 3 Ultra-Absorbent Microfibre Cloths in the box, washable, so there is always a dry one ready
• Use it dry or with a glass spray, inside and out, on the windscreen, side windows, rear glass and mirrors, and at home on mirrors and hard-to-reach windows

Its limits, honestly: on a very wet morning any cloth gets damp, so swap to a dry one rather than keep wiping. It does not replace a proper demist with the blowers before you drive. And if the film is stubborn, a little glass spray helps. You have 60 days to return it if it isn't for you.

FAQ

Should I clean the inside or the outside first?
The outside first. Once it is clean, any streak you still see is on the inside, which makes the inside easier to get right.

Can I use household glass cleaner on my car windows?
Usually, yes, on untinted glass. If your windows have an aftermarket tint film, check the label and avoid ammonia-based products. Keep the spray off the dashboard.

Why do I only see streaks when the sun is low?
Low sun lights up the film on the inside of the windscreen from behind. The streaks were there all along; the angle of the light makes them visible. Oncoming headlights at night do the same, which is why a clean inside screen matters for night driving too. Our article on night driving glasses covers glare in more detail.

Does vinegar work on car windows?
A splash of white vinegar in water is a common home mix and works on light grime. Buff the glass dry afterwards, and keep it off paintwork and rubber seals.

How do I stop the inside getting dirty so fast?
Keep the dashboard dusted, avoid wiping mist with your hand, and give the inside a quick clean every few weeks in winter. For the wider picture, see why your car gets dirty so quickly.

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About the author: Laura Pemberton writes the product copy and blog articles at Vauscher. She also works on product research, helping select the home, garden and DIY products in our range.