Abstract: A high capacity machine cuts the tops of plastic bottles and inverts the bottles for discharging their contents. Bottles are conveyed through the machine by a feed screw. At the cutting station means are provided for standing the bottles erect so that they engage a stationary knife just below the top for cutting off the caps. Guides downstream from the cutting station maintain the bottle in the screw and invert it underneath the screw for dumping. The cap is not completely severed but a minor portion of the circumference is left intact to serve as a hinge between the cut bottle and cap. The cap is kept more or less erect as the bottle is inverted to avoid interference with discharge of the contents. At the cutting station a support screw is rotated synchronously with the feed screw by interengaging teeth on the crests of the threads of the two screws.