For streak-free car windows, use an ammonia-free glass cleaner and two clean microfiber towels: one to wipe and a dry one to buff. Clean the outside after you’ve washed the car, and on the inside, spray the towel instead of the glass.
Streaks almost always come from a dirty towel, too much cleaner, or hot glass. Fix those three and most of the problem goes away.
Time: A short job. It takes longer if the inside glass has a heavy film.
Difficulty: Easy.
What you need
- Ammonia-free glass cleaner
- Three or four clean microfiber towels, ideally a type made for glass
- Rubbing alcohol and water, for stubborn haze (optional)
- A window cleaning wand for the base of the windshield (optional)
The wipes and towels page covers which microfiber works on glass, and the sprays and cleaners page covers glass cleaners.
Why ammonia-free matters
Aftermarket window tint is a thin plastic film on the inside of the glass, and ammonia can damage it over time. Tint installers actually use ammonia products to take tint off. Blue household glass cleaners typically contain ammonia, so check the label before you use one in your car.
Factory tinted glass is different, because it isn’t a film and can handle commercial glass cleaners. But you may not know what you have, especially on a used car, so ammonia-free is the safe habit on every window.
Chemical safety: Never mix bleach with ammonia or any other cleaner, and that includes vinegar. Keep the doors open while you work inside. Follow the label, and wear gloves if it tells you to.
Cleaning the outside glass
Wash the car first with the two-bucket method, so you aren’t grinding road grit across the glass. Then:
- Park in the shade. Warm glass dries the cleaner before you can wipe it, which is how you get streaks.
- Lift the wipers. Raise them off the glass so you can reach underneath. Lift them by the arm, and set them down gently when you’re done.
- Spray one window at a time. A light mist is plenty. More cleaner just means more to buff off.
- Wipe with your first towel. Use firm, overlapping passes. Fold the towel to a clean side once it starts to look dirty.
- Buff with your dry towel. Go over the glass right away until it’s clear. This second pass is what removes the streaks.
- Lower each side window a little. Clean the strip along the top edge that hides in the door seal. It’s easy to miss, and it shows up later as a dirty line.
- Wipe the wiper blades. A damp towel along the rubber edge stops them from smearing dirt back onto clean glass. If they still streak, it may be time for new wiper blades.
If spots stay behind after all this, they may be mineral deposits, which glass cleaner won’t move. See how to remove water spots from a car.
Cleaning the inside glass
The inside gets a greasy film that a quick wipe tends to smear around. It builds up from materials in the cabin off-gassing, from some air fresheners, from smoking or vaping, and even from everyday breathing. You’ll notice it most when driving toward the sun or at night.
- Dry wipe first if the film is heavy. A dry microfiber towel takes off the worst of it, so you aren’t just spreading it around.
- Spray the towel, not the glass. This keeps cleaner off your dashboard, screens, and door panels.
- Wipe the glass in sections. Sitting in the passenger seat makes the far side of the windshield easier to reach. A wand helps at the base, where the glass meets the dash.
- Change towels when the grime spreads. If the towel stops lifting the film, it’s loaded. Switch to a fresh one.
- Buff with a dry towel. Look at the glass from a low angle, because that’s where haze shows up.
- Go along the rear defroster lines. On the rear window, wipe in the same direction as the lines, and don’t scrape at them.
For stubborn film: Jalopnik suggests a 1:1 mix of rubbing alcohol and water, or a 1:1 mix of vinegar and water, sprayed on a clean cloth. Keep the mix on the towel, and off your dash and upholstery. Use one product at a time, and wipe it away before you try another.
If you have aftermarket tint: Stay gentle. Use a soft microfiber towel with an ammonia-free cleaner or plain water, and don’t over-wet the edges of the film.
Common mistakes
Using a towel with fabric softener or wax on it. Residue in the towel ends up on the glass. Keep a set of towels only for windows and wash them separately.
Cleaning in direct sun. The cleaner flashes off, and you get streaks no matter how careful you are.
Reaching for ammonia on tint. The damage is gradual, which is why people don’t connect it to their cleaner. By the time the film peels or fades, it’s too late.
Using a magic eraser on the inside. They’re abrasive and can ruin aftermarket tint.
Skipping the second towel. A single damp towel moves cleaner around. The dry one takes it away.
Forgetting the mirrors and the top edge. These small areas make a freshly cleaned window look unfinished. Go back for them.
Spraying the inside of the windshield. Overspray lands on the dash and can leave marks there. Spray the towel.
When to hire a pro
Most glass is a simple home job. Bring in a detailer if you have baked-on mineral spots that won’t come off, or if a heavy smoke film keeps coming back. Scratches and pitting in the glass are a different matter, so talk to a glass shop. If your tint is bubbling or peeling, a tint installer is the person to see.
If you’d like the glass done as part of a full clean, you can find a detailer near you.