A packaged cosmetic product is provided which includes multiple effervescent sachets placed within a tub with an open dispensing mouth. A carbon dioxide breathable and moisture barrier foil is arranged sealingly to close the dispensing mouth. Any carbon dioxide generated during storage, usually as a result of moisture prematurely effervescing powder within the sachets, is allowed to slowly diffuse into the atmosphere through the window formed by the special foil. The tub is formed of walls which do not have any substantial carbon dioxide breathability but do prevent inward moisture penetration.