Office Chair

I need a gas cylinder to remove from an office chair. I would not buy one of those special tools for removal, but if I can help it. They are too expensive, just for once. Turn the chair upside down. Trying to find a hollow metal tube (maybe a vacuum tube) site on the edge of the cylinder, put a piece of wood on the end of the tube, so you do not harm them, and turn sharply with a hammer. It would help if someone could be to cut down on the chair up at the same time. Be careful not to take, but with a hammer. Can a few valves. To open the window in the second or third floor and throws it as far as you can.