Abstract: A method for cold lidding open-top containers with roll-stock elastomeric film by holding a web of the film in air-tight relation across the bottom of a lidding chamber and about its periphery, evacuating the lidding chamber to stretch the web thereinto, inserting the top of the container into the lidding chamber, and releasing the stretched web over the top of the container whereby the inherent restorative characteristic of the web causes it to quickly contract, i.e. "snap" onto the periphery of the container to form a dynamic seal. The removal of the lidded container from the apparatus causes the container to be moved against a tripper plate to ready the apparatus for lidding the next container. The minimum recovery factor of the stretched film web sould be about 85%.