You spend an hour on the windows, everything looks perfect – and the next morning the low sun reveals every streak and smear. It's one of the most frustrating cleaning jobs. The trick to clean windows without streaks isn't an expensive spray. It's timing, the right tools, very little detergent and a clear sequence.
Swiss homes often have large windows, balcony doors and tilt-and-turn windows with wide frames, so it's worth getting the technique right. Here are five tricks that professional window cleaners use every day.
Why windows get streaky
Streaks are residue: dirt that has been moved around instead of removed, detergent that stays on the glass, or minerals from tap water that dry on the surface. Hard water, which is common in many parts of Switzerland, makes this more visible. Microfibre cloths that have been washed with fabric softener, and paper towels that leave lint, add to the problem.
The solution is to use little product, lift the dirty water off the glass completely and dry the edges carefully.
1. Choose the right time and weather
Timing matters more than most people think.
- Avoid direct sun: Do the sunny side of the building in the morning or evening, or on an overcast day.
- Avoid heat: On hot summer days the glass warms up and water evaporates in seconds.
- Avoid frost and strong wind: Both make streak-free results almost impossible.
- Mild, cloudy days in spring, late summer and autumn are ideal.
2. Clean frames and sills first
If you clean the glass first, dirty water from the frame runs down onto the clean pane.
- Open the window and vacuum or brush dust and insects out of the frame rebates and tracks.
- Wipe frames and sills with warm soapy water and a cloth.
- Wipe the rubber seals gently with a damp cloth – no solvents.
- Only then move on to the glass.
For yellowed or grey plastic frames, see our separate guide on cleaning window frames.
3. The right cleaning solution: less is more
You don't need special window cleaner. The Swiss consumer protection foundation also recommends simple household remedies instead of many special products.
| Solution | When to use | Tip |
|---|---|---|
| Lukewarm water + a drop of washing-up liquid | Everyday dirt, most windows | Too much soap causes streaks – a few drops per bucket are enough |
| Water + a splash of vinegar or spirit | Greasy film, kitchen windows | Keep vinegar away from natural stone sills |
| Clear water only | Final wipe on very lightly soiled glass | Change the water often |
Change the water as soon as it looks grey – dirty water is one of the main reasons windows stay streaky.
4. Strip washer and squeegee: clean windows without streaks like a pro
This is the method that makes the biggest difference.
- Wet: Apply the solution generously with a strip washer (a T-shaped mop with a cloth cover) or a large sponge. Loosen dirt with a few passes.
- Squeegee: Place the rubber blade at the top corner of the glass at a slight angle. Pull it down or across in one smooth stroke, with light, even pressure.
- Wipe the blade: After each stroke, wipe the rubber with a dry cloth.
- Overlap: Each stroke should overlap the previous one by a few centimetres.
- Edges: Dry the edges and corners with a well-wrung, lint-free microfibre cloth.
Check the rubber regularly: a nicked or hardened blade leaves lines. Replacement rubbers are inexpensive.
No squeegee? Use two microfibre cloths: one damp to clean, one dry to polish immediately. Work in straight lines, not circles.
5. Safety first: ladders and high windows
Falls at the window are a real risk. The Swiss Council for Accident Prevention (BFU) recommends a stable stepladder instead of chairs or boxes and no acrobatics at the window.
- Use a stable stepladder with a safety bar and non-slip feet. The BFU explains what to look for in a stepladder.
- Never lean out of the window or climb onto the window sill.
- For the outside of fixed windows, use a telescopic pole – or leave the job to professionals.
- Wear closed, non-slip shoes.
Common mistakes when cleaning windows
- Cleaning in blazing sun: Water dries into streaks before you can remove it.
- Too much detergent: Leaves a film that attracts new dirt.
- Newspaper and paper towels: Leave lint and ink smears.
- Dirty water: Just spreads the dirt evenly.
- Glass first, frame second: Dirty water runs onto the clean glass.
- Circular wiping: Creates swirls that show in the light.
The same squeegee technique works for balcony glass – see our guide on how to clean a balcony. For mirrors and glass tables, read our tips for streak-free glass surfaces.
Frequently asked questions
What is the best way to clean windows without streaks?
Work in the shade, use lukewarm water with just a few drops of washing-up liquid, apply it with a strip washer and remove it with a squeegee in overlapping strokes. Wipe the blade after each stroke and dry the edges with a lint-free microfibre cloth.
Why are my windows still streaky after cleaning?
The most common reasons are too much detergent, dirty water, direct sunlight, cloths washed with fabric softener or a worn squeegee blade. Change one factor at a time to find the cause.
Can I clean windows with vinegar?
Yes, a splash of vinegar in water helps with greasy films, for example on kitchen windows. Protect natural stone sills, as acids can damage them, and rinse the frames with clear water.
Should I clean windows inside or outside first?
Many professionals do the outside first, so you can tell afterwards which side any remaining streaks are on. What matters more is cleaning the frames before the glass.
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