A button-like body formed of a thin elastic material is provided with a plurality of slots which intersect with one another adjacent the center of the body to define a plurality of triangular resilient prongs having adjacently disposed pointed inner ends located in close proximity to one another. The body, except for a rim portion, is cone-shaped with an upturned rim which surrounds a part of a convex outer side of the conical portion. Radially disposed reinforcing ribs are provided for the prongs on the concave inner side of the conical portion. The prongs are spread by a part of the open end of a garbage can liner bag, which is turned back over the rim of a refuse can, for drawing said part between the prongs from the concave to the convex side of the body, sufficiently to tighten the open mouth of the bag around the exterior of the can to prevent collapsing of the bag into the can. After the bag is substantially filled, the bag mouth is disengaged from the can and the remainder thereof is drawn through the button-like body to provide a closure for the filled bag.