Abstract: A bag of tubular form open at one end and closed at the other end, consisting essentially in the combination of: an outer tube comprising one or more contiguous plies of non-heat sealable, flexible sheet material, such as paper, and an inner tube comprising a ply of heat sealable, plastic sheet material, all of the plies being bonded together at both ends of the bag, with the inner ply otherwise detached from the outer tube, the outer tube having thermal transmission and flexibility properties such that the inner tube may be heat sealed to closure and severance thereat by compressive heat and creasing pressure applied to the outer tube, the inner tube being heat sealed to closure and terminated by severance adjacent the closed bag end, and the outer tube being closed thereat beyond the closure of the inner tube thereat, the bag being closeable at its open end after commodity charging, by heat sealing to closure and severing the inner tube adjacent the open bag end and then closing the outer tube thereat beyon