How to Whiten Curtains and Sheers
To whiten yellowed or greyed curtains and sheers, soak them before washing in warm water with oxygen bleach (sodium percarbonate, a gentle oxygen-based whitener), or baking soda for a light greying. White vinegar in the rinse water revives the white and softens the fabric. Then wash at a low temperature. Avoid chlorine bleach on most fibres: it yellows synthetics and weakens fabrics over time.
A sheer can be whitened as long as the fibre is sound; too worn or permanently greyed, it is better to replace it. Kurtens makes curtains custom to the exact size, to start again on a clean base.
Why curtains and sheers turn yellow
A white sheer greys and yellows over time: dust, smoke, damp, sun and detergent residue build up in the fibre. The white first dulls to grey, then turns yellow on synthetic fabrics exposed to the sun. The good news: as long as the fibre is not burnt by UV, this veil lifts off with gentle products, without harming the fabric.
Oxygen bleach, the most effective method
Sodium percarbonate is an oxygen-based whitener, gentler than chlorine bleach and safe for most fibres. Dilute one to two tablespoons per litre of warm (not hot) water, immerse the sheer and let it soak for one to two hours. The oxygen released lifts the grey and the yellow. Then machine wash at a low temperature. It is the method that performs best on a dulled white.
Baking soda and white vinegar, the gentle methods
For a light greying, baking soda is enough: half a cup in the soaking water, or straight into the machine drawer. It revives the white and neutralises odours. White vinegar, added to the rinse water (one glass), dissolves the limescale and detergent residue that dull the fabric, and softens it. The two combine without risk and suit regular care.
Washing and drying without re-greying
Whitening only holds if the wash follows. Wash at a low temperature (30 °C) with a detergent suited to whites, without overdosing: too much detergent leaves a film that re-greys. Rinse well. Dry the sheer in the shade, never in full sun behind glass, which re-yellows synthetics. A sheer still slightly damp hangs straight back up and finishes drying without creases. For the rest of curtain care, see how to care for technical curtains.
Mistakes to avoid
Do not reach for chlorine bleach by reflex: it permanently yellows polyester and nylon, and weakens cotton and linen with repeated use. Do not wash a synthetic sheer in very hot water, heat sets the yellow. Do not overdose the detergent, it is what re-greys. Do not dry in full sun behind a window. And always check the care label before soaking a delicate fabric.
When the sheer no longer whitens: custom
A sheer whose fibre is burnt by UV or permanently greyed will not return to its original white, whatever the product. At that point, replacing it costs less time than yet another soak. Kurtens makes curtains custom to the dimensions of your window, in a range of colors and fabrics, delivered ready to hang, to start again on a clean and well-sized base. You give your measurements, the curtain arrives at the right size. See the Kurtens custom curtains.
How do you whiten curtains?
If the care label allows it, soak the curtain for one to two hours in warm water with sodium percarbonate, one to two tablespoons per litre. Then wash it at 30 °C on a delicate cycle, with a glass of white vinegar in the rinse water. Dry it in the shade. The Kurtens 3-in-1, however, is dry clean only.
The label comes before any product. Its triangle shows which bleaching is allowed: crossed out, no bleach at all; marked with two diagonal lines, only an oxygen bleach such as percarbonate. Avoid chlorine bleach, which yellows synthetics.
Among Kurtens curtains, the 3-in-1 and the noise-reducing acoustic curtain are never soaked and never go in the machine: they are dry cleaned by a professional. The linen-effect sheer and the single-layer blackout curtain are machine washable; their care instructions forbid chlorine, and our care guide for technical curtains recommends a mild detergent with no bleaching agent for them. So ask customer service before using percarbonate, baking soda or vinegar.
How do you whiten white curtains that have turned grey?
If the care label allows it, add half a cup of baking soda to the soaking water or to the machine drawer, and a glass of white vinegar to the rinse water, which dissolves limescale and detergent residue. If the grey persists and the label accepts an oxygen bleach, soak the curtain in sodium percarbonate before washing it again.
Baking soda is enough for a light greying; for a more dulled white, percarbonate is more effective. For Kurtens curtains, the limits in the previous section apply: the 3-in-1 and the acoustic curtain are dry clean only, with no soaking; for the linen-effect sheer and the single-layer blackout curtain, ask customer service before using percarbonate, baking soda or vinegar.
Frequently asked questions
How do you whiten yellowed sheers?
Soak them for one to two hours in warm water with oxygen bleach (sodium percarbonate), then wash at a low temperature. Add white vinegar to the rinse to revive the white. Avoid chlorine bleach, which yellows synthetics.
Can you whiten curtains with baking soda?
Yes, for a light greying. Add half a cup of baking soda to the soaking water or the machine drawer. It revives the white and neutralises odours, without harming the fibre. For a marked yellow, use oxygen bleach instead.
Does chlorine bleach whiten sheers?
On pure white cotton, occasionally yes, but it permanently yellows polyester and nylon and weakens fibres over time. For a synthetic sheer, sodium percarbonate is safer and more effective.
Why do my white sheers turn yellow?
Dust, smoke, damp, detergent residue and sun build up in the fibre. Synthetics exposed to UV behind glass yellow the fastest. A white vinegar rinse and drying in the shade slow the process.
What temperature to wash a white sheer?
At a low temperature, 30 °C, on a delicate cycle, after a whitening soak if needed. Hot water sets the yellow on synthetics. Dry in the shade and hang the sheer back up still slightly damp to avoid creases.
Whitening a sheer is simple as long as the fibre is sound; too worn, it gets replaced. To start again on a clean base at the right size, have your curtains made as Kurtens custom curtains, delivered ready to hang.
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