a system for forming and mounting end closures for peel - top containers , each closure including a peelable sealing membrane , with a folded pull tab , and a separate plastic overcap . the individual sealing membranes are cut from a continuous web and deposited directly on the open ends of cans or containers being fed in a continuing line . each membrane is retained in properly oriented association with the corresponding container , by adhesive tacking or through a partial vacuum generated within the container , until such time as the container supported membrane is engaged by a chuck to effect a positive sealing of the membrane to the container . after a sealing of the membrane to the container , the container proceeds through a cycle wherein the tab on the membrane is laterally bent , the overcap is applied , and the container with completed end closure is discharged . embossing of each membrane is normally selectively done so as to occur only over the area thereof inward of the peripheral portion which engages the container .