Abstract: A bung comprises a deformable member with a generally cylindrical middle portion generally coinciding with the bunghole when inserted, and upper and lower frusto-conical ends which increase in diameter as each end extends from the middle portion. The middle portion is preferably of a size less than the hole to facilitate insertion of bung into and removal from the bunghole. Where the hole is tapered, the middle portion is similarly tapered. The spool-like shape of the stopper helps to prevent unintentional disengagement of the bung from the hole and to prevent overinsertion of the bung into the hole. The bung may further comprise one or more pull tabs to facilitate removal. The bung may define a bore to allow gas pressure to escape from the container, thus acting as a stopper. A rigid annular insert at the opening of the throughbore prevents deformation of the circular shape of the opening.