We recommend cleaning your oil diffuser after 5-6 uses. Unplug the unit from the power adaptor and remove the cover from the water tank. Pour out any remaining water. Use a damp cloth, and a small amount of mild dish soap to clean the inside of the water tank, wipe gently and dry with a clean cloth, like the one provided with your diffuser. Remember to keep water from flowing into the three-air outlets located on the bottom of the water tank, by pouring water out using the sides of the water tank. Do not use any acid or enzyme detergents, as this may give off poisonous gas and/or cause the unit to malfunction. Keep atomization piece inside of the water tank clean using warm water, mild dish soap, and the provided cleaning brush or a cotton swab. For additional information and illustrations, please refer to the instruction manual included with your product.