How to Remove Mould and Mildew From Silk

Mildew grows in moist, warm places that are not well ventilated or lack sunlight, and it discolours silk. You may notice the smell of mildew before you can see it. Fortunately, in many cases you can lift it with hydrogen peroxide.

Before you start. Hydrogen peroxide is a mild bleach. It will lift some mildew staining, and it will weaken silk fibres with repeated use. Treat it as an occasional last resort on white or pale silk only, never on colour, and always well diluted. If the piece is dyed, printed or precious, take it to a dry cleaner who handles silk instead.

1. Take the item outside, wear gloves, and brush off as much surface mildew as you can with a soft brush. Bag the debris, wrap the bag in paper and bin it, so you are not shaking spores back through the house.
2. Air the silk in a warm, well ventilated spot out of direct sun until it is completely dry. Mildew needs damp to keep going, so drying it first does half the work.
3. Patch test. Mix one part 3% hydrogen peroxide with four parts cool water, dab a little on a hidden seam, leave it ten minutes, then rinse and let it dry. Compare it against the rest of the piece before you go any further.
4. If the test is clean, soak by hand in a basin, not the washing machine. Use the same one part 3% peroxide to four parts cool water, keep the water below 30 degrees, and leave it no longer than 15 to 30 minutes. Do not use full strength peroxide, and do not leave silk soaking for hours.
5. Rinse thoroughly in cool water until no peroxide smell remains, then wash gently with a silk friendly detergent. Roll in a towel to blot, and dry flat or on a hanger away from direct sun and heat.

If the mark survives one careful treatment, stop. A second and third round will cost you more in fibre strength than the stain is worth. Our full silk care guide covers everyday washing, and how to whiten yellowed silk covers the related problem of age yellowing.