Abstract: An uncasing and sorting machine for refillable plastic bottles includes a first conveyor arrangement having an inlet section, an intermediate section, and an outlet section, the intermediate section being positioned within a water bath. Crates of sortable bottles are carried by the first conveyor through the described sections such that lightweight plastic bottles are allowed to float within the water bath. To assist in the upward lift of the lightweight bottles in the water bath, a secondary propulsion force of air or water is provided beneath the bottles. Those bottles which are lifted due to their combined buoyancy and the secondary propulsion force, are transported to a separate facility via a secondary conveyor of either mechanical or air type.