Each humidifier user guide contains instructions on cleaning that specific type of device and its components. In general, the water tub should be washed every day in warm water with a mild detergent, then rinsed thoroughly with clean water and left to dry away from direct sunlight. Every month, the water tub should be inspected for wear and deterioration and replaced if any component is cracked, cloudy or pitted.  Patients should not use any of the following to clean their humidifiers as these solutions may cause damage and reduce the life of the product: Bleach, chlorine-, alcohol- or ammonia-based solutions Moisturising, antibacterial or glycerine based soaps, Water softening and unapproved descaling agents For your convenience, here are the cleaning instructions for ResMed’s heated humidifier: Every day Wash the disassembled tub lid, plate and base in warm water using a mild detergent. Rinse thoroughly in clean water and allow them to dry away from direct sunlight. Every month Peel the flip lid seal from the flip lid and wash it in warm water using a mild detergent. Wipe the exterior of the humidifier with a damp cloth and mild detergent. Please note that the disassembled tub lid, plate and base may also be washed in a dishwasher on the delicate or glassware cycle (top shelf only). White powder deposits in the water tub can be removed using a solution of one part household vinegar to 10 parts water.