A method and apparatus for selectively demetallizing a metallized film whereby the metallized web is selectively demetallized by bringing the web into contact with two electrodes, one of which contacts a greater surface area of the web than the other, and maintaining an electrical potential difference between the two electrodes. Preferably, the electrodes comprise rollers, one of which may be provided with a predetermined pattern. The potential difference between the respective electrodes can be controlled to effect selected demetalization of predetermined desired regions of the web or to vary the extent of demetalization from a desired region. The web material can subsequently be used as microwavable packaging material.