Abstract: Objects are packed in respective receptacles in a unitary body of sheet material having orifices open in a common direction. An annular edge portion of the body envelops the orifices and one or more rib portions of the body separate each orifice from each other orifice. A cover of sheet material is superimposed in a vacuum chamber on the edge portion and the orifices and sealed gastight to the edge portion. When the body with the sealed cover is exposed to atmospheric pressure, the cover is pressed by the air against the rib portions and may be sealed thereto. The sealing die employed in this process need only clamp the edge portion of the sheet material body against a suitable backing die.