Use Froggy's Fog Fully Clean Fog Machine Cleaner cleans out deposits left in your water-based fog machine's heater core during normal use. This will restore your machine, optimizing performance, helping to prevent clogs that can occur during normal use. This 1 gal allows you to clean and maintain a number of machines, as it takes about a cup of the cleaning fluid to routinely service a single machine. The cleaning fluid should be used when storing a machine for periods longer than a month or about once every three months during regular use.