Abstract: A capsule 11 for enclosing a neck portion of a container 17 equipped with a bung, cork, screw-cap or other closure 18 is formed from a crimp-shaped capsule blank. The blank has a top 12 and a depending skirt 13 and is made by impact-extruding a strip of aluminum. The skirt is compressed inwardly into close contact with the neck portion of the container and the exposed laterally-facing surfaces of the closure 18. The skirt of the blank may have an increasing diameter in a direction away from the top and may have formed thereon prior to application of the blank to the container circumferentially-extending lines of weakness 14 and a tear-tab for facilitating removal of the capsule.