1, which can be erased with an eraser;
2. Secondly, remove it with adhesive tape;
3. If it still doesn't work, you can try to scrape off the back of the wallpaper blade. If it is worn, you can paint it.
4. Organic solvents can also be used for dissolution. Using the similar miscibility of organic solvents, you can also apply some gasoline or alcohol, toilet water or essential oil, but the concentration is low. Apply it to the stain, then let it stand for a while and then wipe it carefully.