A plastic bag closer slider has a separator normally resting in notches in the tops of slider track strips, when the slider is at a bag-closed stop. As the slider is moved in the bag-opening direction, the separator is cammed downward by ends of the notches to disengage interlocking profile features and open the tag. In another embodiment, notches are omitted. The separator is manufactured with a normally down position but is resiliently biased upward when the bag is closed. As the slider is moved in the bag-opening direction, the pointed end of the separator wedge descends between the strips to open the bag. When the slider is moved in the bag-closing direction, the separator is cammed upward by the drag of the strip tops and the tapering walls of the slider squeeze interlocking profile features together, closing the bag.