The invention relates to a cover for opening and closing cans, in particular beverage cans, having a top circular cover component and a bottom cover component. By moving the two cover components relative to one another, at least one through-hole can be opened and re-closed by both cover components. A highly effective seal is obtained by precise coordination of the form of the top and bottom cover components, which can be increased even further by the additional use of sealing materials such as varnish, rubber, plastic or welded connections.