Abstract: A releasably mountable cleanout cover for releasable mounting onto a plumbing cleanout cap, having a protruding cap member, exposed within an aperture in a wall includes an aperture covering member having an exterior surface and an interior surface for covering the aperture in the wait, a hollow mounting tube rigidly mounted to and generally centered on, the interior surface and extending longitudinally and generally perpendicularly outwardly from the interior surface, a longitudinally spaced apart array of opposed inwardly extending resilient flanges spaced longitudinally apart within the hollow mounting tube for resilient deformation about opposed surfaces on the protruding cap member when the protruding cap member is snugly journalled in the hollow mounting tube so as to be snugly retained between the opposed inwardly extending resilient flanges.