Spread the tissue on a flat surface and wipe it off by stroking the brush. Put lukewarm water on a bowl and add a small amount of neutral detergent for clothes (fashionable clothes wash, etc.). Soak about two-thirds of the bristles of the brush and remove the dirt so that it will loosen. At that time, be careful not to get the base of the brush wet. After rinsing and removing the detergent, drain it with a tissue, shape it, and dry it in the shade until it dries well. Please note that insufficient drying may cause the growth of germs.