Only attempt disposal of the balloon tank when it is empty. Confirm the cylinder is empty by fully opening the valve by turning it to the left.
Take the tank to a well-ventilated area. Fully open the valve handle by turning it counter-clockwise. Press and hold down on the tilt-nozzle until the tank is empty.
Listen and feel for pressure discharging from the tilt-nozzle. The tank is empty when no sound is heard or pressure is felt. Unscrew and remove the tilt-nozzle either by hand or with the help of a ¾ inch wrench.
Write “EMPTY” in bold text with a permanent marker on the balloon cylinder near the blowout valve, so that it is clearly visible.
Locate the blowout valve on the shoulder of the balloon cylinder.
Using a slotted (flat-head) screwdriver, position the head in the depression at the edge of the ring.
Using a mallet or hammer, tap the handle of the screwdriver lightly but firmly. Repeat in multiple places around the ring edge, until the metal ring covering the blowout valve is punctured.
Carefully, completely open the rupture disc. With a permanent magic marker, draw a large circle around the open rupture disk and write the word “EMPTY” on the tank.