Abstract: Gaseous ozone is admixed and stored with water under such conditions that the density of ozone in the water is increased above the normally obtained and held stabily at such levels so that it may be efficiently transported through the processing plant being cleaned. Specifically, the present invention provides for the chilling of the ozone and water carrier to increase density and permit the subsequent increase in temperature to cause propulsion of the water and ozone through the plant to be cleaned in-place.