Clean glass is the part of a detail you notice every time you drive, and streaky glass is the part you notice most, especially at night or into a low sun. This guide explains why car windows streak, what to use, and how to clean the outside, the inside and the windscreen properly, with the glass cleaners and glass cloths we stock and each maker's own instructions.
How do you clean car windows without streaks?
Use a dedicated car glass cleaner and two clean glass cloths. Work in the shade on cool glass, spray the cleaner onto the cloth, wipe with firm pressure, then buff with a dry cloth or a clean dry side. Clean the inside and outside separately, and keep wax and dressing off your glass cloths.
Why do car windows streak?
Stjarnagloss puts it simply: streaks and smears are usually down to a poor glass cleaner, an unsuitable cloth, or both. A few other things make it worse:
- Hot glass or direct sun, which dries the cleaner before you can wipe it off.
- A cloth that has picked up wax, polish, tyre dressing or fabric softener and now smears it around.
- Too much product, which leaves more residue than the cloth can lift.
- The oily film that builds up on the inside of the windscreen, which takes more than one pass to clear.
What you need
Every pick below is in stock with us, and every claim comes from the maker's own listing or website.
A glass cleaner
- Stjarnagloss Glas: a glass cleaner that Stjarnagloss designed for glass and clear plastics.
- CarPro Clarify: a dedicated glass cleaner that CarPro says cuts through grime without damaging a hydrophobic glass coating or rain repellent. CarPro lists it for traffic film, oils, fingerprints, dirt and contamination, inside and outside the glass.
- CarPro Clarify Phobic: an instantly hydrophobic glass cleaner. CarPro says it leaves a highly hydrophobic layer that improves visibility and reduces wiper chatter, on coated glass to top it up or on uncoated glass as part of regular cleaning.
- ValetPro Glass Cleaner: its listing describes a streak-free finish with a hydrophobic glass seal, and says it is safe on mirrored surfaces, tint and plastic.
- Dodo Juice Clearly Menthol, a glass cleaner from Dodo Juice.
Glass cloths
Glass cloths have a tighter, flatter weave than general cloths, so they lift residue instead of pushing it around:
- FibreKing Gold Label Korean Glass Cloths: 40 x 40cm, with a 2mm sponge layer inside. FibreKing says the high density, pile-free weave removes moisture, dust and fingerprints without leaving streaks or lint.
- FibreKing Carbon Glass Cloths: 40 x 40cm, 350 GSM, woven with carbon fibre threads that FibreKing says give better static control.
- FibreKing Waffle Weave Towels: 40 x 40cm, 300 GSM, which FibreKing says are exceptional for glass.
Our guide to the best microfibre cloths for cars explains how to wash and look after them.
How do you clean the outside of car windows?
- Wash the car first, so you are not dragging grit across the glass. Our guide on how to wash your car safely covers it.
- Work in the shade on cool glass.
- Spray the cleaner onto the cloth rather than the glass. CarPro's method for Clarify is 1 or 2 sprays onto a glass cloth.
- Wipe the glass with the damp cloth using firm pressure.
- Flip the cloth to a clean, dry side, or use a second dry cloth, and buff away any residue.
- Lift the wipers and wipe along the rubber blades with a damp cloth, so they do not smear dirt straight back onto clean glass.
How do you clean the inside of the windscreen?
The inside is harder because of the angle and the oily film that builds up behind the dashboard.
- Spray onto the cloth, never onto the glass, so no cleaner runs down onto the dashboard.
- Clean one half of the windscreen at a time, reaching in from each front door.
- Wipe in one direction on the inside and the other direction on the outside, for example across inside and up and down outside. If a streak is left, its direction tells you which side it is on.
- Buff with a dry glass cloth. A second pass with fresh cloths clears any film that is left.
Should you use a hydrophobic glass cleaner or screen wash?
A hydrophobic product leaves a layer that makes rain bead and run off, which helps visibility in bad weather. You can apply it as part of cleaning, with CarPro Clarify Phobic on dry or wet glass, or top it up every time you use the washers with a hydrophobic screen wash:
- ValetPro Ceramic Washer Fluid: a concentrated screen wash that its listing says creates a hydrophobic coating and is safe for all windscreens, including tinted ones.
- Sonax XTREME Clear View: a 1:100 screen wash concentrate, so 25ml makes 2.5 litres and the 250ml bottle makes 25 litres. Its listing says it removes oils, grime, insects and silicone films and is safe on glass, paint, rubber and LED or Xenon headlights.
Before winter, check that the screen wash in your reservoir protects against frost.
Glass products compared
Notes are the makers' own, as shown on each product page or the maker's website.
| Product | Type | Maker's note |
|---|---|---|
| Stjarnagloss Glas | Glass cleaner | For glass and clear plastics |
| CarPro Clarify | Glass cleaner | Safe on coated glass and rain repellent, inside and outside |
| CarPro Clarify Phobic | Hydrophobic glass cleaner | Leaves a hydrophobic layer, reduces wiper chatter |
| ValetPro Glass Cleaner | Glass cleaner | Hydrophobic seal, safe on tint and plastic |
| ValetPro Ceramic Washer Fluid | Screen wash concentrate | Hydrophobic coating, safe on tinted windscreens |
| Sonax XTREME Clear View | Screen wash concentrate | 1:100, 250ml makes 25 litres |
Need help choosing?
Tell the TDHQ team what you need to clear, from road film to an oily inside screen, and we will point you to the right products. You can also browse every glass cleaner and glass cloth we stock, or read the correct order to detail a car, where glass comes last.
Last updated 1 October 2026.
