Streaks are rarely bad luck. They come from five things you can control, and once you control them, glass dries clear. Here is why streaks happen, the five-part formula, a squeegee routine, an interior method and a rescue for panes you have already streaked.
In This Article
Why streaks happen
- Too much soap. Extra soap leaves a film that streaks as it dries.
- A dirty blade or cloth. Grit and old residue get dragged across the next pane.
- Drying too fast. Sun and wind dry the mix before you clear it.
- Minerals in the water. Hard water dries into spots and streaks.
- Oils on the glass. Fingerprints, kitchen grease and skin oil repel water unevenly.
- Lint. Paper towels and some cloths leave fibres behind.
Notice that none of those is about how hard you rub. Streak-free glass is a matter of clean tools, the right amount of liquid and timing.
The five-part formula
| Variable | Get it right | What goes wrong |
|---|---|---|
| Water | Clean, and low in minerals if you can manage it, or squeegee everything dry. | Hard water left to evaporate leaves spots. |
| Soap | A small squirt of mild dish soap in a bucket of water. | More soap means more film and more streaks. |
| Tools | A clean sleeve, sharp undamaged rubber and fresh microfibre. | A nicked blade draws lines across the whole pane. |
| Technique | Pre-rinse, overlapping strokes, and a wipe of the blade after each pull. | Skipping the blade wipe re-deposits dirty water. |
| Conditions | Overcast, calm, above freezing, and shade if possible. | Sun and wind dry the glass before you clear it. |
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A short kit that covers most windows
- A squeegee with a replaceable rubber, and a spare blade.
- A channel a little narrower than your typical pane, so one stroke covers the width.
- A washer sleeve or strip washer that holds mix without dripping.
- Three or four microfibre cloths, kept for glass only and washed without fabric softener.
- A bucket, a spray bottle and a small towel to tuck under the sill.
Check your rubber before every session. Run a fingernail along the edge. If it catches on a nick, or the edge has rounded off, the blade will streak, and a replacement costs far less than the time you spend redoing windows.
The squeegee routine, step by step
- Clear the frame and sill. Wipe or brush off loose dirt so it does not wash onto clean glass.
- Wet the glass. Work the washer sleeve from the top down, scrubbing corners and edges where dirt builds up.
- Start the first stroke at the top. Angle the blade slightly and pull it down along one edge in a single, steady stroke.
- Overlap and repeat. Each new stroke overlaps the last by a few centimetres. Wipe the blade on a clean cloth after every pull.
- Detail the edges. Run a dry microfibre cloth along the bottom edge and around the corners, where water hides and drips.
- Check from an angle. Look along the glass in side light and buff any smears away with a clean, dry cloth.
Small panes suit a horizontal pull in an S shape, and large panes a straight vertical pull. Choose the pattern that keeps your blade moving in one motion. Hold the squeegee at a slight angle with light, even pressure. Pressing hard makes the rubber chatter, and a blade held flat leaves water behind.
Interior windows: the microfibre method
Dust the sill and frame first. Then lightly dampen a microfibre cloth with an ammonia-free glass cleaner or a little soapy water. Spray the cloth, not the glass, so nothing runs onto the sill and frame. Wipe the inside in horizontal strokes, then buff with a dry cloth.
A trade trick helps with diagnosis. Wipe the inside horizontally and the outside vertically, and any streak that remains shows its direction, so you know which face it is on. Skip paper towels, which leave lint, and do not clean glass in direct sun, where the cleaner flashes off and streaks.
Fixing a streaky pane
- Soap film: rinse the pane with plain water and squeegee it again.
- Oily marks: rub gently with a cloth lightly dampened with isopropyl alcohol, then rinse and dry. Keep alcohol away from window film and coatings.
- Cleaner residue: rinse with clean water and buff.
- White spots that came back: they are minerals, not streaks. See how to remove hard water stains.
If a window keeps streaking despite clean tools and the right conditions, the cause is often minerals in the rinse water or a damaged blade. D&D Home Services quotes window cleaning from $125 for typical Kitchener-Waterloo homes. Read how professionals get streak-free windows, and see window cleaning for what a visit involves.
Key Takeaways
- Streaks come from too much soap, dirty tools, fast drying, mineral-rich water, oils and lint, not from too little effort.
- Control five variables: water, soap, tools, technique and conditions.
- Use a small squirt of mild soap, overlapping strokes and a blade wipe after every pull, and work in calm, overcast, above-freezing weather.
- Fix a streaky pane by rinsing off soap film, dissolving oils with a little isopropyl alcohol and treating white spots as minerals.
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