Turn your humidifier off or to the "0" position and unplug the electrical cord. Detach the water tank and remove it from the rest of the Vicks Kaz humidifier.
Fill a dishpan with warm water and a squirt of mild dishwashing detergent.
Release the cooling chamber interlock to separate the cooling chamber from the base. Place the cooling chamber and medicine cup in the detergent solution to soak.
Fill a bucket halfway with white vinegar. Add warm water to fill the remainder of the bucket. Place the water tray in the bucket and allow it to soak for 20 minutes to remove limescale and mineral deposits. Pour the vinegar out, rinse the water tray with water and dry it with a clean cloth.
Pour full-strength vinegar into the heating chamber until it's full. Allow the vinegar to remain in the heating chamber for 20 minutes. Empty almost all of the vinegar out of the heating chamber, leaving enough to wipe the inside with. Wet a clean cloth with the remaining vinegar and wipe inside the heating chamber to remove loosened mineral deposits.
Wash the cooling chamber and medicine cup that were soaking in the detergent solution. Rinse them with warm water and dry them with a clean cloth.
Allow all components of your Vicks Kaz humidifier to air-dry completely before reassembling them and turning your humidifier on again.