A multilayer stack of polymeric sheets can be used in thermoforming processes to make objects wherein each sheet has substantially the same shape. The stack includes at least one sheet of a thermoformable polymer, and can include many such sheets. A barrier layer is interposed between at least an overlapping portion at least two of the polymeric sheets in order to prevent fusion of the sheets in the overlapping portion during the thermoforming process. The barrier layer can include an adhesive that adheres the sheets in the overlapping portion. In formed articles including such an adhesive, the sheets can be manually peeled from one another if a suitable adhesive is selected. The stack (and object formed using the stack) can include polymeric sheets that are not thermoformable, but are adhered to the surface of a thermoformable sheet. The sheets and objects can include multiple separable and/or peelable sheets. The stack can be used, for example, to make peelable, re-usable food service trays. In such trays, a rigid base has multiple peelable sheets adhered to at least one surface thereof, the sheets being peelable from the surface to reveal a sanitary surface amenable to food contact.