Abstract: A dish-shaped insert for a cylindrical container of cosmetic dusting powder or the like has a slightly upwardly and outwardly tapering peripheral wall terminating in a narrow flange. An integrally formed, protruding, circumferential rib extending around near the midpoint of the wall cooperates with one or more recesses at the upper edge of the container wall to permit escape of air as the insert is pressed into the container and then to seal the container when the rib passes the bottom of the wall recess, so that fine powder and product fragrance do not escape. The insert is injection molded or, preferably, thermoformed of thermoplastic sheet material and may bear one or more tabs to facilitate removal as well as indicia such as a trademark or name.