Short answer
If your windows were cleaned with soap or detergent before, old residue can sit in the frames and seals and run onto the glass for the first few cleans. It can take two or three cleans to clear. That comes from trade and manufacturer sources, not a test, so treat it as a rule of thumb.
What is the residue?
Traditional window cleaning uses soap or detergent. Some of it can stay in the seals and frames after the glass looks clean. When pure water goes over those frames, trade sources say old residue can run out and onto the glass. It’s a few spots, not a failed clean, and it tends to show on the first visits and then fade.
How long can it take?
The sources I’ve read say two or three cleans. I can’t tell from outside how much residue is in your frames, so I can’t promise a number for your home. My advice is to expect a few spots at first and judge the result after the first few cleans. If marks are still there by then, tell me what you see.
That’s one reason I explain this before the first visit. It’s on the outside window cleaning page and in how it works, so it doesn’t come as a surprise.
Is it something I did wrong?
No. It isn’t your windows or your previous cleaner being bad. It’s just the way residue behaves when the glass and frames are rinsed with water that has nothing in it. Pure water is very good at lifting what’s there, and that includes old soap.
What else leaves spots?
Trade sources also name causes that have nothing to do with old soap:
- Dirty vents above the glass. Dirt in a trickle vent can run down onto the pane.
- Oxidised aluminium frames, or old paint that runs onto the glass. These show as marks that keep coming back.
- Water that isn’t pure enough, or a poor rinse. That points to the cleaning, so tell me.
- Hard water drying on the glass. If water that still has minerals in it is left to dry, it leaves white spots. That’s what pure water is meant to avoid. Does hard water leave spots on windows? explains it.
If spots keep coming back after a few cleans, one of these may be the reason, and I want to hear about it.
What can I do to help it clear faster?
Not a lot, honestly, and that’s fine. Tell me about the frames when you send your request: whether they’re uPVC, aluminium or timber, and whether the paint is cracked. Cleaning uPVC window frames and sills covers what I do around frames. And try not to wipe the spots yourself with a cloth. That can smear them, and it doesn’t solve where they’re coming from.
Common questions
Should I call you straight away if I see spots?
Tell me, yes, but give it a short while to dry fully first. Wet glass can look spotted when it isn’t. Then let me know where they are and I’ll look.
Will you come back and look?
If marks are my cleaning and not residue from your frames, I’ll want to put it right. Tell me what you see and I’ll say what I think it is.
Can I stop it happening?
You can’t fully, but a little help is to avoid soapy cleaners on the frames before my first visit.
Is it worth switching from a traditional cleaner?
That’s your call, and I won’t knock anyone else’s work. If you do switch, expect the first few pure-water cleans to show a few spots while old residue clears from the frames. After that, the glass should dry clear. If it doesn’t, tell me.
Do spots show more on some windows than others?
Often on windows with older seals or busy vents above them, because there’s more for the water to carry out. If one window keeps spotting while the others clear, tell me which one, and I’ll look at the frame and vent above it.
What happens next?
If you live in Rayleigh or Wickford and you’d like windows that settle down after a few visits, get a quote and tell me what your frames are like.
