Quick answer: Clean on a cloudy day rather than in direct sunlight, spray a vinegar and water solution or washing-up liquid mix onto the glass, wipe with a zig-zag motion using a microfibre cloth, then pull a squeegee down the glass in a single stroke to remove the water completely. Buff any remaining marks with a dry, lint-free cloth.
Streaky windows are almost always a technique problem rather than a product problem. Get the timing, tools, and method right, and even an ordinary bottle of white vinegar will leave glass looking properly clear. This guide covers why streaks form in the first place and exactly how to avoid them.
Why Windows Streak
Streaks usually come down to one of a few causes. Cleaning solution evaporating too quickly leaves soap or mineral residue behind before you can wipe it away properly. Using too much product creates a greasy film. Dirty water or an old cloth simply redeposits grime rather than removing it. And hard water, common in much of the UK, leaves mineral streaks of its own once the water dries.
Choose the Right Day
Pick a cloudy day if you can. Direct sunlight heats the glass, causing your cleaning solution to evaporate before you have time to wipe it off properly, which bakes streaks onto warm glass that are then harder to shift. If you must clean on a sunny day, work on the shaded side of the house, or clean early morning or in the evening once the glass has cooled.
What You Will Need
- A soft brush or vacuum brush attachment, for loose dust and dirt
- A spray bottle
- White vinegar, or washing-up liquid
- A squeegee, ideally with a 25 to 30cm rubber blade
- Several clean, dry microfibre cloths
Step 1: Clear Away Loose Dirt First
Wipe down the window frames, handles, and sills before touching the glass. Dirt and grime here can transfer onto the glass and cause fresh scratches or smears if you skip this step. A soft brush or a vacuum with a brush attachment works well for loose dust on the glass itself.
Step 2: Mix Your Cleaning Solution
Two simple options work well for most homes.
White Vinegar Solution
Mix equal parts white vinegar and water in a spray bottle. Vinegar’s mild acidity cuts through everyday grime and helps counter mineral streaks from hard water, without leaving a residue behind.
Washing-Up Liquid Solution
For greasier windows, mix around half a teaspoon of washing-up liquid into 500ml of water. Use this sparingly, since too much soap is one of the most common causes of a greasy film and streaking.
Step 3: Apply and Wipe
- Spray the solution generously over the glass, working from top to bottom.
- Wipe in a zig-zag motion rather than circles or straight lines, which spreads the solution more evenly and helps you see any missed patches as you go.
- Keep your cloth or applicator moving in a continuous motion across the glass, rather than lifting off and reapplying, which tends to leave overlap marks.
Step 4: Squeegee for a Streak-Free Finish
A squeegee is the single biggest upgrade if you are still seeing streaks with a cloth alone.
- Starting at the top corner, pull the squeegee down the glass in one smooth, continuous stroke.
- Wipe the blade dry with a cloth after each stroke, then overlap slightly with the next pass.
- Work your way across the whole window, wiping away any water that collects on the sill as you finish.
Step 5: Buff With a Dry Cloth
Finish with a dry, clean microfibre cloth to buff away any last streaks or water spots, particularly around the edges where a squeegee cannot always reach cleanly. Use a fresh cloth for this step rather than the one used for applying the solution, since a damp cloth will simply reintroduce moisture.
Dealing With Hard Water Marks
If you live in a hard water area and notice persistent white, chalky marks even after cleaning, this is mineral deposit rather than dirt. Undiluted white vinegar left to sit for a few minutes before wiping tends to cut through this more effectively than a diluted spray. For particularly stubborn marks, some households use deionised water, which has had the dissolved minerals removed, so it evaporates without leaving any residue at all.
How Often Should You Clean Your Windows?
For most UK homes, twice a year, once in spring and once in autumn, is generally sufficient. Clean more often, roughly every two to three months, if you live near a busy road, since traffic film builds up quickly, in a coastal area, where salt spray affects glass, or in an area with high pollen during certain seasons.
Related Guides
- How to Clean uPVC Windows (for frame, hinge, and seal care beyond the glass)
Frequently Asked Questions
Why do my windows still have streaks after cleaning?
The most common causes are cleaning in direct sunlight, using too much soap, or not finishing with a squeegee and dry cloth. Address these three factors first before assuming the problem is your cleaning solution.
What is the best homemade window cleaner?
A simple mix of equal parts white vinegar and water works well for most everyday dirt, while a small amount of washing-up liquid in water tackles greasier marks more effectively.
How often should you clean your windows?
Twice a year is enough for most UK homes, though busy roads, coastal locations, and high pollen periods call for more frequent cleaning, roughly every two to three months.
Does vinegar damage window frames?
Vinegar is generally safe on glass but can affect certain surfaces like marble sills, so cover or avoid spraying it directly onto other materials nearby.
Final Thoughts
Streak-free windows come down to timing, technique, and finishing the job properly with a squeegee and a dry cloth, rather than needing an expensive specialist product. Pick a cloudy day, do not overdo the soap, and work in a steady, overlapping motion for a clear, professional-looking result.