Abstract: A cover for enclosing the open top of a container, such as a liquid waste receptacle. The cover comprises an annular support dimensioned to fit generally coaxially within the open top of the container. The annular support defines an opening for passage of materials therethrough and into the container. The cover further comprises a mechanism for releasably securing the annular support to the upper edge margin of the container, a straining element in the annular support having a straining area coextensive with substantially the entire area of the opening in the annulaar support for straining solid objects of a predetermined maximum dimension from entry into the container while permitting entry of liquids through the opening and into the container, a lid dimensioned for covering the opening in the annular support, and a hinge for securing the lid to the annular support.