In order to ensure your humidor remains at optimum humidity, you will need to charge your humidifier at intervals: 1. Remove the humidifier from the humidor 2. Using the grate, squirt a specialist humidifying solution, or plain distilled water, into the humidifier. Only use a small amount of liquid, as the aim is to moisten the humidifier, not soak it through 3. Using a dry cloth, wipe any excess solution from the front of the unit 4. Replace the humidifier in the lid of the humidor