To be accurate, IR thermometers must be kept clean. To clean, use a soft cloth or cotton swab with water or medical grade rubbing alcohol and carefully wipe first the lens and then the body of the thermometer. Allow the lens to dry fully before using the thermometer. Never use soap or chemicals and never submerge any part of the thermometer in water. Industrial IR thermometers should be cleaned when dirty, or roughly every six months according to some manufacturers. Consult the instructions for your device before cleaning. Clinical IR thermometers used for temperature screening should be cleaned and disinfected according to manufacturer's instructions and facility policies, according to the Centers for Disease Control and Prevention.