Soapy water. The silicone strap with grease should be coated with soapy water, wipe the stain with a soft cloth, and then wash it with water. Dry the water with a napkin or a soft cloth and leave in a cool, ventilated place to dry. Dish soap. First wet the silicone watch strap with water (note that because some watch heads can not be water, so it depends on whether the watch core you use has waterproof function, if you do not remove the watch head first), then add a little dishwashing liquid, gently wipe with a small brush, and then wash with water.