We recommend changing your AuraPod filter every 1-3 weeks to avoid dust and particle buildup. NOTE* Every AuraPod comes with a free replacement filter. HIGH QUALITY: The filter sticks are made of premium cotton to increase water absorption and ensure the normal work of our diffusers. SAFE BREATHING: Changing your filters every 2-3 weeks or when using a new scent is important to ensure your air is pure and your AuraPod works as it should. HOW TO USE: Soak the cotton stick in water for 1 minute before use to make the cotton stick completely wet.