Abstract: The invention relates to the formation of antimicrobial solutions formed by ozonating a liquid containing organic precursor molecules. The preferred organic precursor molecules include carboxylic acids, most particularly octanoic acid with or without acetic acid, and alcohols, most particularly greater than 80 weight percent ethanol. The ozonating step is preferably performed with minimal or no water present in the liquid containing the organic precursors. After ozonation is complete, the ozonated liquid may be diluted with water or other solvent to form a use solution for contacting and cleaning a microbially contaminated surface or other medium.