Cleaning windows in direct sunlight

People blame their technique for streaky windows when the real culprit is usually the weather: washing glass in direct sunlight evaporates the cleaning fluid within seconds, leaving detergent film baked onto the pane before you can clear it.

Why it backfires

Glass cleaner is designed to loosen grime and stay wet until you remove it. In sun and heat, the water in it flashes off, the residue sticks, and every pass of the cloth just pushes the dried film around. The harder you work, the hazier the window — a perfect metaphor that has sold a lot of unnecessary products.

The fix

Pick a cloudy, mild, still day (or the shaded side of the house), and work with two cloths and one squeegee: wash with a modest amount of cleaner, then pull it off in overlapping top-to-bottom strokes, wiping the squeegee blade between passes. Finish the edges with a dry microfibre cloth. Almost no product is needed for a regular clean — a drop of washing-up liquid in warm water is the professional window-cleaner's honest toolkit.

Keep it from happening

Twice a year is plenty for outside glass; inside, as needed. And the same evaporates-before-you-finish principle explains a family of cleaning frustrations: cleaning a car in the sun, leaving product to dry on shower glass, polish that hazes before you buff. Cool and damp beats strong and fast in almost every cleaning job there is — the seasonal checklist times the year's bigger jobs by the same logic.