Why Most Windows End Up Streaky

Almost every smeared window has the same three culprits: too much soap, too much water, and a cloth that has given up long before it touched the glass. Washing-up liquid is a brilliant degreaser, but it leaves a film if you use more than a drop or two, and that film dries into the very streaks you were trying to remove. Hot, sunny days make it worse — the solution dries before you can wipe it off, baking marks into the pane.

Hard water is the other quiet offender. If you live in a chalky area, tap water leaves behind calcium deposits that look like fog and feel slightly rough to the touch. The fix isn't more effort; it's a better sequence and less product.

The Two-Cloth Method That Actually Works

You need two clean microfibre cloths — one for washing, one for finishing — and they must stay separate. Mixing the jobs is how streaks happen.

• Cloth one (the washer): damp, not dripping. Wipe the glass in slow, overlapping lines, working from the top corners downwards so dirty water runs onto the area you haven't cleaned yet.
• Cloth two (the buffer): dry and fresh. Follow immediately behind, buffing in a circular motion, then finishing with a straight pass along the edges.
• Fold each cloth into quarters so you have eight clean surfaces. Swap to a fresh face when it starts to feel slick or grey.
• Never use fabric conditioner when washing microfibre. It coats the fibres and turns a good cloth into a smearing machine.

For interior glass, this alone is often enough — no squeegee required, no drips on the sill, and nothing to rinse.

Getting the Solution Right

For a typical bucket of warm water — around four to five litres — you need no more than two or three drops of washing-up liquid. That's it. Swirl it gently; you don't want a mountain of foam, because foam is just soap waiting to dry on the glass.

In hard water areas, swap to one part distilled white vinegar to four parts water. It cuts through limescale and evaporates cleanly. A few cautions worth knowing: don't use vinegar on natural stone sills, and avoid it on older aluminium frames or any seal you're unsure about. Cooled boiled water or collected rainwater both work beautifully as a final rinse if your tap water is particularly mineral-heavy.

Skip the temptation to add bleach, ammonia, or a squirt of this and that. Simple is clearer, every time.

The Squeegee Technique, Step by Step

A 25cm squeegee handles most domestic windows well; go smaller for awkward sashes and conservatory panels. Dampen the rubber blade before you start — a dry blade judders and leaves lines.

• Wet the whole pane with your washing cloth first, then squeegee while it's still wet.
• Start at the top and pull horizontally, tilting the blade slightly so water collects along the top edge rather than spilling.
• Overlap each stroke by about two centimetres so you don't leave a stripe between passes.
• Wipe the blade on a cloth after every single stroke. This is the step people skip, and it's the one that matters most.
• Finish the bottom edge with a dry cloth, then buff the corners where water pools.

Outside, work top to bottom and don't let runoff dry on the frame. Inside, keep a cloth under the squeegee to catch the drip line along the sill.

Frames, Sills and Stubborn Marks

Clean glass sitting in a grubby frame will look grubby again within a week. Give UPVC frames a wipe with the same mild solution and a soft cloth, then dry them — residue attracts dust, and dust migrates onto the glass.

For limescale speckles on shower screens or conservatory panels, lay a vinegar-soaked cloth against the glass for ten minutes and let the acid do the work rather than scrubbing. Paint splashes come off with a plastic scraper held at a shallow angle. Sticky label residue lifts with a little warm soapy water and patience. Avoid abrasive pads on glass; a single scratch catches light and can't be undone.

Timing, Routine and a Lighter Footprint

Choose an overcast day. Bright sun is the enemy of streak-free glass because it dries your solution before you've finished the pane. Early morning or late afternoon works well, and it's kinder on your arms too.

A sensible rhythm: a quick interior buff once a month, a full two-cloth and squeegee session every season, and an outside clean twice a year — more often if you're near a busy road or under trees. Reusable microfibre cloths and a refillable spray bottle cut out a surprising amount of plastic, and a single bottle of white vinegar will last you years.

Once you've got the two-cloth habit, window cleaning stops being a chore you dread and becomes a fifteen-minute job you can finish with a cup of tea in hand.