A lot of the older stoves, have a combination fuel filler and pump with an inner sleeve in it. It's impossible to pour out the fuel. Stick the plug in the filler, put the one hose in your mouth and pressure it up...takes about 30 seconds max to drain a tank.
The other smaller one is made by Dave A. Same type of tool, but you plug it into the lantern or top fueling stove, and pressure it up with the pump....same results...dumps fuel in a hurry. If it doesn't fit the older 242's...just hold it on with your hand...it'll seal up well enough to empty it.
I defueled 10 stoves and 8 lanterns in about 45min max...and that includes running upstairs and down with the tanks. Doug