PureAir air purifier virtually maintenance-free. On the smaller units (models 50LV, P100, P300, PA500) there is nothing to maintain unless the Device is located in a very dusty or smoky area, then we recommend opening the unit up once in a while and wiping off the ultraviolet lamp with a soft cloth, Some accumulations on the bulb (i.e., chemicals from tobacco smoke) may require rubbing alcohol to remove. On our larger units (model PR500, PZ, SP series) the small stainless steel mesh filter on the back of the unit may accumulate dust and may need to be clean up by a vacuum cleaner.