The screen windows are full of dust. Because the mesh is too large, all the air is sucked by the vacuum cleaner, and the dust cannot be absorbed. We can use tape to stick the newspaper on the screen window, and then use a vacuum cleaner to absorb it from the other side, and the dust can be cleaned relatively clean.  If there is no vacuum cleaner or it is inconvenient to enter the other side, the following little trick is also fine.  Take some flour, add water to make a thin batter, quickly brush on both sides of the screen and spread it evenly. After waiting for more than ten minutes, the batter has absorbed the greasy on the screens. At this time, I used a brush to brush it several times, and the greasy fell off with the batter. Rinse again with water, and the oil stains are gone.