People regularly ask us which window cleaning product to buy, expecting the name of something professional and expensive. The honest answer surprises them every time: washing-up liquid. A few drops in warm water performs the same as branded window cleaning soap, and better than any spray on the supermarket shelf.
The Secret Nobody Sells
The solution is the least important part of cleaning a window. Dirt comes off glass through the scrub and the tools — the mop that loosens it, the squeegee that removes it, the cloth that finishes the edges. Soap just helps the water glide. Once you know that, spending money on a “special formula” makes no sense, because no formula scrubs anything.
Why Sprays Disappoint
The spray-and-wipe method fails for a reason we explain in full in our guide to the most common window cleaning mistake: the solution dries into the glass while you wipe, and the cloth leaves lint behind. You end up polishing streaks into the pane rather than lifting dirt off it.
What the Professionals Use Instead
For exterior work we do not use soap at all — purified, deionised water on a water-fed pole dries spotless with nothing left behind. Indoors and on traditional work it is exactly what we have described: mild solution, mop, squeegee, dry cloth. The kit list is short; the technique is the trade. We cover the full setup in the tools professional window cleaners actually use.
The Practical Takeaway
Save the money on sprays. Washing-up liquid, warm water, a decent squeegee and the right order of operations will get you 90% of the way to a professional finish — and for the windows you cannot safely reach, we are a two-minute quote away.