1, alcohol or 84 disinfectant treatment method: firstly, use a brush or a dry rag to remove mildew spots on the wall, and then wipe the wall with a towel dipped in alcohol; 2, bleaching powder method: first wipe the mildew spots with a towel dipped in alcohol, and then fully mix bleaching powder with water in the ratio of 1: 99, and then spray it on the moldy wall. 3. Eradication method: Use a small shovel to eradicate mildew spots, then apply waterproof paint and repaint.

Causes of moldy walls: 1. The wall is moldy, probably because the drain pipe and warm air pipe leak, which will lead to the wall being damp and moldy. 2. Cracks appear in the external wall, and rainwater seeps into the wall, resulting in moisture in the wall. It may also be caused by the poor sealing of the window and the rain pouring into the room.

3. The temperature difference between indoor and outdoor is large. It may be that the wall insulation is not done well, resulting in a large temperature difference between indoor and outdoor. The water vapor in the indoor air is precooled and condensed on the wall, which will cause the wall to be wet for a long time.

Harm of moldy wall to human body: After moldy wall, many biological bacteria will breed, and wall mold will flow with the air, and long-term exposure and inhalation will cause respiratory diseases. Therefore, moldy walls do great harm to human body. If mildew is found, it should be treated as soon as possible to avoid harm to the body.