Why Your Windows STILL Have Streaks After Cleaning

You followed the instructions. You bought the "streak-free" cleaner. You watched the videos. You spent an hour on a Saturday morning carefully cleaning every window in the house.

In Short

Streaks after cleaning are a technique problem, not a product problem. A streak is the residue left behind when dirt, soap, or minerals are moved across the glass instead of removed from it. The seven causes are the wrong cleaner, too much soap, hard water, direct sunlight, paper towels, poor squeegee technique, and skipped edge detailing. The fix is the professional method: a few drops of dish soap in water, a scrubber, a squeegee wiped dry between passes, and a lint-free microfiber cloth along every edge.

Then the afternoon sun came through and there they were. Streaks. Everywhere.

After 25 years of cleaning windows professionally, from residential homes in Melbourne to high-rise buildings in Vienna, I can diagnose window streaks the way a mechanic diagnoses engine noise. And in almost every case, the cause is one of seven things that nobody talks about.

Cause #1: You're Using the Wrong Cleaner

Your "streak-free" glass cleaner is probably creating the streaks. The fix: a few drops of dish soap in a bucket of water.

Cause #2: Too Much Soap

More soap does not mean cleaner windows. Excess soap creates a film on the glass.

Cause #3: Your Water Is Working Against You

If your tap water has high mineral content, those minerals stay on the glass as white spots.

Cause #4: You're Cleaning in Direct Sunlight

When sunlight hits wet glass, the cleaning solution evaporates faster than you can squeegee it off.

Cause #5: You're Using the Wrong Tools

Paper towels leave streaks. Always. Without exception. What actually works is a squeegee, scrubber, and microfiber cloth.

Cause #6: Your Squeegee Technique Is Off

Wrong angle. Stopping mid-stroke. Not wiping the blade between passes.

Cause #7: You're Detailing Wrong (Or Not At All)

The last 10% of the job creates 90% of the visible streaks. One pass with a lint-free microfiber cloth along each edge.

The Quick Diagnosis

• Streaks everywhere: Too much soap or wrong cleaner
• White spots or cloudy film: Hard water minerals
• Streaks that appear quickly: Sunlight evaporation
• Tiny fiber marks: Paper towels or cotton cloth
• Lines running vertically: Edge water dripping down
• Random streaks: Dirty squeegee blade

The streaks end here. Download "The Window Cleaning Manifesto", FREE 5-minute training.

If you want the technique taught properly, step by step, start with my window cleaning course. Step 1 is free.

Frequently Asked Questions

Why do my windows still have streaks after cleaning?

Because streaks come from technique, not from the product you used. In 25 years of professional window cleaning I see the same seven causes: the wrong cleaner, too much soap, hard water minerals, cleaning in direct sunlight, paper towels, a squeegee held at the wrong angle or not wiped between passes, and edges that were never detailed. Fix the technique and the streaks stop.

Does streak-free glass cleaner actually work?

Usually it is the cause of the streaks, not the cure. Spray cleaners leave a film on the glass, and more product makes it worse. The professional solution is a few drops of dish soap in a bucket of water, which lifts the dirt without leaving residue.

What is the best way to clean windows without streaks?

Use a scrubber to dissolve the dirt, a squeegee to remove the water, and a lint-free microfiber cloth to detail the edges. Wipe the squeegee blade dry between passes, and never clean glass in direct sunlight because the water evaporates before you can squeegee it off. Paper towels leave streaks every time.

Why do white spots appear on my windows after cleaning?

White spots or a cloudy film are hard water minerals. If your tap water has a high mineral content, those minerals stay on the glass when the water dries. Streaks everywhere point to too much soap or the wrong cleaner, while tiny fiber marks point to paper towels or cotton cloth.