Short answer
For normal uPVC, wash frames and sills with warm water and a little mild washing-up liquid on a soft cloth, then rinse and dry. Avoid abrasive pads, bleach and strong solvents, which can scratch or dull the plastic. On my outside visits, I scrub frames and sills with a soft brush and pure water as part of the clean.
Why do frames matter?
Glass is only part of how a window looks. If the frame and sill are grubby, the dirt runs onto the glass when it rains or when the glass is rinsed, and the window looks dirty again quickly. Cleaning the glass and not the frame is the quickest way to be disappointed. That’s why I include frames and sills in an outside window clean.
What can I use on uPVC myself?
The advice from uPVC makers and cleaning guides is similar:
- Warm water and a little mild washing-up liquid, applied with a soft cloth or sponge.
- A soft brush for tracks, seals and corners.
- A clean, dry cloth to finish if you want, though it isn’t essential.
Rinse off any soap so it doesn’t leave residue. That residue is one of the things that can run out of frames on a later clean, which spots after the first clean covers.
What should I avoid?
- Abrasive pads and powders, which scratch the surface and make it hold dirt.
- Bleach and strong solvents, which can dull or discolour the plastic.
- Pressure washers close to the frame, which can force water past seals. A gentle rinse is fine.
- Silicone sprays and polishes you haven’t tested, as they can leave a film that attracts dust.
If you aren’t sure whether a product is safe, test a small hidden spot first.
What do I do on a visit?
If you’d like the frames and sills done, ask me: the soft brush can scrub them while pure water flows through it. Pure water has no minerals in it, so it dries without leaving marks. I can’t promise to lift every stain: old yellowing, deep scratches and weathering aren’t dirt. If I think something won’t shift, I’ll tell you rather than scrub at it.
What about tracks, seals and vents?
Tracks and seals hold grit that’s hard to reach. A soft brush helps, and a vacuum with a nozzle works well on dry tracks. Trickle vents collect dust and spiders. Cleaning them now and then helps stop dirt running onto the pane. What to do before the window cleaner comes covers what I’d like you to do first.
After building work, frames need extra care with grit: window cleaning after building work.
What about cracked paint or other frame types?
This page is for uPVC. Timber frames, painted frames and aluminium frames need different care. If paint is cracked or flaking, tell me before the visit, because brushing can lift it. The same goes for oiled or varnished timber. What is a water-fed pole? has more on when I ask first.
Common questions
Can I use a magic sponge or melamine eraser?
Some people do, but they work by being very slightly abrasive, which can leave a dull patch on glossy plastic. If you try one, test a hidden corner first and use very light pressure. I don’t use them on frames.
Why do my white frames look yellow?
Yellowing usually comes from age, sunlight and weathering of the plastic rather than dirt on top. Cleaning shifts dirt, not yellowing, so I’d rather tell you that than scrub away at it and leave you disappointed.
How often should I wipe the sills?
Whenever you notice dust, spiders' webs or grit collecting. Sills catch the most, and wiping them between visits keeps the dirt from running onto the glass. There’s no fixed interval; it depends on the weather and how close the window is to trees or a road.
Does it matter which way I wipe?
Work from the top of the frame downwards, so dirty water doesn’t run over parts you’ve just done. Finish with the sill and the track.
Should I clean frames before glass?
Yes. Clean from the top down: frame, then glass, then sill. That way dirty water runs over parts you haven’t done yet, not parts you’ve finished.
