The best method to remove mould stains from plaster walls

Updated February 21, 2017

Mould is a fungus that can grow in damp areas in the home, such as bathrooms, utility rooms and attics. It is an allergen that irritates the eyes, ears, nose and throat. Asthma sufferers are especially sensitive to mould. Once it takes hold in the home, it will grow, causing black stains on walls and furnishings. Eliminate mould as soon as you spot it in your home. After that, you can remove the stains it leaves behind.

Mix a solution to kill the mould. The solution should consist of 250 ml (1 cup) of white vinegar, the same quantity of 3 per cent hydrogen peroxide (not the strong peroxide used to bleach hair, but rather the weaker version used as a disinfectant and sold in drugstores), and 60 ml (2 fl oz) boric acid. Pour into a spray bottle and shake well to mix.

Put on a surgical mask. Spray the solution heavily on to the mould and a 30 cm (1 foot) surrounding area. Mould spores may have spread beyond the area where it is currently visible.

Let the solution stand for about ten minutes, and then wash off the dead mould using paper towels and water. Discard the towels immediately after use.

Spray the area one more time with the above solution, wait ten minutes, and then wash it off. All of the mould should have been killed by the boric acid-vinegar-peroxide mixture -- however, this mixture is not a stain remover. A stain will remain wherever there was mould.

Mix a solution of 1 litre (4 cups) of water to 250 ml (1 cup) of chlorine bleach. Scrub the stain using scouring pads soaked in the bleach solution. Repeat this step as many times as necessary to remove the stain.

Eliminate the source of the dampness from your home, if at all possible, or the mould will return. If you can't find the source, or can't eliminate it, keep a close eye on areas where the mould appeared, and at the first signs of new mould forming, use the same solutions to eliminate it.

Things You'll Need

  • White vinegar
  • Hydrogen peroxide (3 per cent solution)
  • Boric acid
  • Chlorine bleach
  • Surgical mask
  • Paper towels
  • Scouring pads
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About the Author

J.M. Pence has written magazine articles and essays for a variety of publications, including “Sunset,” “Mystery Scene,” “Cat Fancy,” and “Idaho Magazine,” plus 15 novels, a novella, and several short stories. Published since 1987, Pence holds a master's degree in journalism and a B.A. in history with a minor in political science from U.C. Berkeley.