How to remove stains on walls without removing the wall paint

Use sodium bicarbonate and water
Sodium bicarbonate is a natural and soft cleaning agent that can be used to remove blemishes on walls. Mix a tablespoon of sodium bicarbonate with water to form a paste. Apply the dough to the stain and leave to act for a few minutes. Gently rub the blemish with a soft brush or sponge, then wipe it with a damp cloth. Repeat if necessary.