uPVC windows and doors should be cleaned with warm water, a mild detergent and a soft cloth. Abrasive creams, bleach, solvents and WD40 all damage the surface, and some of that damage cannot be reversed.
This guide covers the frames, sills, glass, seals, drainage and hardware, along with what to do about paint, mould and yellowing. It also explains how coloured and textured finishes need slightly different care from plain white uPVC.
Frames need cleaning two to four times a year. Properties near a main road, an industrial estate or the coast sit at the upper end of that range, because traffic film and salt build up faster. Rural properties can usually manage with a clean twice a year. Glass generally needs attention more often than frames.
A light clean three times a year takes minutes and needs nothing stronger than soapy water. A frame left for several years needs the aggressive treatment that causes the damage this guide warns against, so a regular light clean is also the safest one.
Warm water with a few drops of washing-up liquid, applied with a soft cloth, handles almost all uPVC cleaning.
Marks that resist need a dedicated uPVC window cleaner. The best uPVC cleaners are solvent-free and non-abrasive, used sparingly and tested first on a hidden area, such as the bottom of the frame behind an opening sash.
Never use any of the following on uPVC:
WD40 is a common question, and the answer is no. It is a water displacer rather than a lubricant, it leaves a residue that attracts dirt, and it causes rubber gaskets to perish. Hinges and locks should be lubricated with the product specified by the manufacturer instead, covered further down this guide.
One further reason to be careful: damage caused by an unsuitable cleaning product is unlikely to be covered by a product guarantee. It is worth knowing that before reaching for whatever is under the sink.
The best way to clean uPVC window frames is in a set order: dry before wet, and top before bottom.
Step one matters more than it looks. Washing grit into a frame drags it across the surface and leaves fine scratches, and those scratches then hold dirt, which is why a neglected frame can still look grey after cleaning. Removing the loose material before any water is involved prevents that damage. The same applies to PVC and uPVC sills, which collect the most grit of any part of the window.
Cleaning uPVC window frames on the outside follows the same sequence. Upper-floor windows that cannot be reached safely from inside are a job for a window cleaner rather than a ladder.
A front or back door is handled all day, so it picks up finger marks and grease around the handle that a window never does. Warm soapy water and a soft cloth still work on the door panel itself.
The threshold is worth doing first. That is the raised strip running across the bottom of the doorway, where grit gathers and gets walked into the house, so brushing or vacuuming it out before washing saves doing the job twice.
Handles, letterplates and knockers are usually metal rather than uPVC. A barely damp cloth is enough, followed by drying straight away, because water left sitting around the fittings can leave marks.
Frames first, glass second. Runoff from a dirty frame will mark glass that has just been cleaned, which is why the glass comes last in the sequence above. This applies to all double glazed windows, whatever the frame material.
Glass cleaner, or a mix of white vinegar and water, belongs on the panes only. It should be kept off the frames and rubber seals, whatever the glass type fitted.
A squeegee pulled in overlapping strokes, followed by a dry cloth along the edges, gives the cleanest finish. Cleaning glass in direct sunlight is best avoided, because the solution dries before it can be wiped away and leaves streaks.
One thing cleaning cannot fix: misting or condensation between the two panes means the sealed unit has failed. That is a repair or replacement matter rather than a cleaning one, unlike ordinary condensation on the room-side of the glass, which has its own causes and ways to prevent it.
A coloured uPVC frame is not painted. The colour comes from a thin coloured layer bonded onto the uPVC underneath, called a foil. It will not flake or peel the way paint does, but it can be marked, so how it is cleaned matters more than on plain white.
Textured matt finishes, such as Anthracite Textured Matt and Black Textured Matt from our Modern collection, have a slightly rough surface that holds dirt. A soft brush lifts more out of the texture than a flat cloth. Abrasives must be avoided completely, because a scuff on a matt surface shows as a shiny patch and cannot be polished out the way a mark on a gloss finish sometimes can.
Grained finishes, such as Anthracite Grey Grained or the Classic collection colours, have a fine directional texture made to look like a painted wood frame. Cleaning along the grain rather than across it lifts more dirt and leaves a better finish. The same applies to timber-look foils such as Grey Oak and Light Oak.
Dark colours show water marks and dust more than white, so drying with a microfibre cloth matters more, not less. Dark foils also feel noticeably warm in direct summer sun; that is normal for the material and not a defect. The full range of finishes is shown on our colour options page.
The right method depends on the type of paint, and using the wrong one causes damage that in most cases cannot be undone.
Wet emulsion. Wiped away immediately with warm soapy water and a cloth, emulsion that has not dried comes off with almost no effort, so it is worth dealing with quickly.
Dried emulsion. Softened with warm soapy water for a few minutes, then lifted with a plastic scraper or the edge of a wooden spatula held at a shallow angle. Never a metal blade, which scratches the frame.
Gloss and other oil-based paint. The difficult case. A plastic scraper takes most of it off; anything left needs a remover that specifically states it is safe for uPVC, tested on a hidden spot first.
Spray paint and overspray. The hardest to remove, because it lands as a fine mist across the whole surface rather than in one spot. On a coloured frame it usually cannot be removed without some damage, and professional help or a replacement sash may be the realistic answer.
White spirit, methylated spirit, cellulose thinners, acetone and ordinary paint stripper will all soften or melt uPVC, and they can strip the finish off coloured frames completely. They are also exactly what most people reach for, which is why paint removal is where the worst cleaning damage happens.
As for painting uPVC deliberately: it is possible with specialist preparation and coatings, but it is rarely the right answer on a foiled or guaranteed frame. That question deserves its own guide.
These look similar but they are three different problems.
Black mould appears on the rubber seal where the window closes. It is caused by moisture in the room, not by a dirty window.
Green algae grows on outside frames that stay damp and rarely get sun.
Grey film on an outside frame is ordinary dirt from traffic and weather.
For mould, a mix of one part white vinegar to four parts warm water, wiped onto the seal, left for a few minutes and then rinsed off, is effective. Bleach is not the answer, because it damages both the plastic and the rubber.
Cleaning mould only deals with the mark, not the cause. Mould that keeps returning means there is too much moisture in the room, and the real solution is preventing condensation on windows rather than repeat cleaning. If it returns in a room that is already well ventilated, the seals may no longer be doing their job.
Drainage slots. The small slots in the bottom of the outer frame let rainwater that gets past the seal drain away. Blocked slots cause water to build up and eventually appear on the inside sill. They are cleared with a soft brush or a cotton bud, never a screwdriver or wire, which damages the drainage path.
Rubber seals. A wipe with a damp cloth keeps them clean and supple. Oil-based products damage the rubber, so they should never be used here. A seal that has gone hard, shrunk or come away from the frame needs replacing rather than cleaning.
Hinges, locks and handles. A light application of the lubricant specified by the manufacturer, once or twice a year, and not WD40. Stiff operation that lubrication does not fix usually means the window needs adjusting rather than more oil. Replacement handles and fittings are available if hardware is past its best.
A lot of what looks like yellowing is dirt. Traffic film and everyday grime build up into a grey or yellow layer that comes off with soapy water or a suitable uPVC cleaner.
True yellowing is different. Prolonged UV exposure changes the plastic itself, and no cleaning product reverses it. Products that claim to whiten uPVC are generally either removing surface dirt or using abrasives that damage the finish.
Modern uPVC is far more UV-stable than the frames fitted in the 1990s, which is one reason uPVC windows remain so popular, and why significant yellowing is mostly seen on older windows. Frames that have genuinely discoloured cannot be cleaned back to white, and replacement is usually the only effective long-term answer.
At DOVISTA, we make and install uPVC windows and doors in twelve colour options across three collections, from classic grained whites and creams through to Anthracite Textured Matt and realistic timber-look finishes, alongside standard gloss white. Every installation is covered by our 10-year guarantee.
Textured and grained finishes are difficult to judge from photographs, so the best way to compare them is in person at our Milton Keynes showroom. For anything else, from care questions to a free quote, our team is happy to help.
No. WD40 displaces water rather than lubricating, leaves a residue that attracts dirt and can cause rubber seals to perish. The lubricant recommended by the window manufacturer should be used on hinges and locks instead, and seals should not be lubricated at all.
No. Bleach attacks the surface of uPVC, causing permanent discolouration and, in some cases, turning white frames brown. It also damages rubber seals. Warm soapy water or a solvent-free uPVC cleaner cleans the frames without harming the surface.
Warm water with a few drops of washing-up liquid and a soft cloth handles almost everything. Stubborn marks need a solvent-free uPVC cleaner, tested first on a hidden area. Abrasive cleaners and scouring pads scratch the surface and should never be used.
Wet emulsion wipes away with warm soapy water. Dried emulsion is softened with soapy water and lifted with a plastic scraper. Gloss paint needs a remover specifically labelled as safe for uPVC. White spirit and paint stripper damage the frame and should never be used.
Grime and traffic film clean off with soapy water or a uPVC cleaner. Yellowing caused by sunlight is a change in the plastic itself and cannot be cleaned out, whatever a product claims.