The Daniel Marshall Special Care Solution is essential to use in your D.M. humidifier to keep mold away and stabilize the humidity level. Simply use 1 ounce of this solution in your humidifier once every 6 months. The remaining time you will continue to use distilled water as usual. The 4 ounce bottle gives you a 2 year supply (1 ounce every 6 months). Daniel Marshall 4 oz Special Care Solution Bottle Details Pre-mixed 4 oz. bottle of 50/50 mixture of propylene glycol and distilled water Regulates the humidity at 70% for a stable humidor environment Naturally anti-fungal Easy to use Directions for Use Shake bottle Open cap Add 1 oz directly into humidification device Set humidifier upside down on paper towel to absorb excess solution Place humidifier back into your Daniel Marshall humidor Repeat in 6 months