Abstract: A container bag made of a thin foldable plastics sheet material includes a rectangular body portion (2) defined by front and rear walls (4) and (6). The central part of the rear wall (6) extends upwardly to define a trapezoidal rib (22). A first rectangular adhesive region (28) is formed on the rear face of the rib (22) along its length, and covered by a readily removable backing strip (30). A second adhesive region (32) is formed on the lower part of the rear wall (6), and also covered by a readily removable backing strip (34).The bag is folded and inserted in the rack on the rear of a passenger seat. A passenger can open out the bag, remove the backing strip (30) and press the adhesive region (28) against the upper portion of the seat in front. The secured bag is then ready to receive used articles. If desired, the backing strip (34) can be removed from the second adhesive region (32) which is then pressed against a lower portion of the forward seat.