An overcap is provided for removably covering an access opening into the interior of a container. The opening in the container defines a peripheral rim and includes an outwardly projecting bead for releasably retaining the overcap. The overcap is defined by a body portion formed to cover the opening of the container and a depending skirt. The skirt extends from the bottom surface of the body portion for a distance sufficient to cover the projecting bead of the container rim. An inwardly directed retaining ring is formed on an inside surface of the skirt for engagement with the projecting bead on the container. A vent is formed within the retaining ring to define a flow path past the retaining ring. The vent may be a spacing rib formed on the inside surface of the skirt with one or more flow channels formed within the retaining ring.