Product review (5 stars): SOAK IN VINEGAR FIRST!!!
EXCELLENT BUT SOAK THEM IN A MIX OF WHITE VINEGAR AND WATER FIRST TO PREVENT MOLDING..
i use a shallow pan that just covers the filter in water, maybe half a cup of vinegar to half a gallon water.. no need to be exact... no need to rinse just drain off and insert into humidifier... makes it last sooo much longer may 3x the life