Black mould can be a common sight in homes during the winter months, but there's a cheap and easy method to prevent it from forming.
Although it's typically used for cleaning up after meals, washing-up liquid can also be used to prevent this problem during the colder months.
The root cause of mould growth is excessive moisture in the air, with condensation being the main culprit.
Condensation occurs when warm, humid air comes into contact with the cold surfaces of your windows or walls, rapidly cooling to form water droplets. This can then create damp spots where mould can flourish.
Spreading black mould behind my bed probably why I'm getting so sick all the time 😑 pic.twitter.com/Fg7fxBfMtv
— Tam. (@c3convertase) September 13, 2025
However, a cost-effective and convenient method to tackle this issue is by applying washing-up liquid to your windows, as this can prevent condensation from forming, thereby reducing dampness and warding off mould.
A bottle of washing-up liquid costs just 63p at Tesco.
Home Things experts have shared: "By taking a small drop of washing up liquid and rubbing it into the condensation-prone window with a dry cloth you can completely stop the issue all together.
"The washing up liquid forms a barrier on the surface of the windows, preventing the water from sticking. So in the space of just a few minutes, you can put a stop to the damp, mould, and mildew that wet windows can cause."
Experts at The Spruce explained the process: "First, you take a clean cloth (I used microfibre) and apply a small amount of dish soap to the cloth.
"Then you simply wipe the window down with the dish soap. While this obviously works to clean the current condensation from the glass, the dish soap also leaves behind a thin layer of film that is supposed to keep it from coming back."
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They added: "I wiped one side of the window with the dish soap, and one side just with a clean cloth, so I could compare the two.
"When I came back a few hours later, the results were already clear.
"The side of the window I used the dish soap on was completely free of any condensation, while the other side had already started to build up again."
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