A cover for sealing a container having an interior chamber that holds a quantity of material therein. A first channel provided on a base of the cover receives a rim on the container's side wall. A first sealing member is provided on the base. A second sealing member provided on the lid is complementary to the first sealing member and is engageable therewith when the lid is moved to a closed position. A flexible bridge extends between the base and the lid. One of the first or second sealing members is a protrusion and the other is a second channel. The protrusion may be received within the second channel when the lid is closed. Pressure may be progressively applied to the lid to zipper the cover into a sealed position. When the lid is in the sealed position material cannot be accidentally or purposefully removed from the interior chamber.