Our Himalayan Salt Crystal Aroma Lamp offers the beautiful fragrance of oils, the delicate glow of light plus the benefit of negative ion generation. It will fill a 10' x 10' room with fragrance in minutes. As long as you keep it filled you can keep it lit continuously. Some keep them lit in the home stairwells also using it as a safety nightlight. To change the fragrance, wash out the glass bowl with hot soapy water and then add the next oil. There is no water mist and no oil droplets to stain anything.