Abstract: Waste receptacles for use by animals, such as laboratory animals and household pets, are provided with an odor barrier of lightweight, non-absorbent, non-water-wettable, granular material, such as paraffin wax coated corn cob granules. The buoyant, non-absorbent, lightweight granular material is also useful as an odor barrier in liquid-containing portable human toilets and generally as an odor barrier for pools or sumps or open containers of odoriferous materials, such as aqueous offal wastes, aqueous waste from food processing plants and odoriferous wastes from other sources, such as industial sources, e.g., paper mills, chemical plants, manufacturing plants and the like. The non-absorbent granular material in animal toilet applications is conveniently retained on a foraminous tray which, in turn, is mounted on a collecting tray for collection of liquid waste percolating downwardly from the granular material into which the liquid waste was originally deposited.