Abstract: A method and apparatus for generating a vapor/gas mixture includes storing a plurality of volatile liquids to provide the vapor component of the mixture, adding predetermined amounts of the volatile liquids and a dilution gas to a container, and thereafter removing the mixture to prepare a second vapor/gas mixture. In one approach, subsequent mixtures are prepared using different volatile liquids as the vapor component. Alternatively, a portion on the first vapor/gas mixture is removed from the container and then additional volatile liquid or dilution gas are added to the container to prepare a second vapor/gas mixture including the same vapor but at a different percentage in the mixture, or including additional vapors not used in the first vapor/gas mixture.