Abstract: A method of cutting and severing any portion of a nonferrous workpiece having a thickness generally equal to or less than 0.90 inches and a thermal conductivity significantly less than metal. A focused jet of CO.sub.2 crystallites (density of 0.03-0.4 g/cm.sup.3) and a gas, pressurized to at least 100 psi, is translated across the workpiece at a velocity of 250-1000 mm/sec, the jet having a converging focus (0.1-0.5 in.sup.2) substantially near the surface of said workpiece (i) to thermally embrittle the workpiece immediately surrounding said focus, and (ii) to fracture the workpiece at said focus by air pressure.