Himalayan Crystal Salt Lamps require very little care and maintenance. If you feel like you wish to wipe your lamp intermittently, switch it off and wipe it with a slightly damp cloth. This does not tend to be necessary though, as the salt seems to be self cleansing. The idea is to leave the lamps switched on permanently to maintain a continuous source of beneficial negative ions. 
If a lamp is switched off for an extended period (a few days or longer), it is recommended that the lamp is covered with an air tight bag. This will ensure that the lamp is sealed off from the moisture in the surrounding atmosphere, keeping it dry. Himalayan Crystal Salt is highly hygroscopic, which means that it naturally attracts moisture from the air. With the lamp switched on, any moisture is consistently evaporated and does not have a chance to accumulate. However, if a globe goes or the lamp is left switched off, the moisture starts to accumulate, drip, create small pools of water and initiate a crystallization of the salt on the lamp and around the base. So, find the place in the room you feel that the lamp fits best, switch it on, and then leave it on permanently. One exception to this, is that, unless specifically being used as a comforting night light, lamps in a bedroom should be switched off at night, to ensure as dark a room as possible and facilitate melatonin production, ensuring a deeper, more restful sleep.