When the canisters are empty, they are simply thrown away. Pure Butane burns very efficiently, but doesn t work well in cold weather. If the temperature is going to be below 50 F. you should consider other types of fuel. Also, pure butane does not burn as hot as other blended fuels. If you will be doing three season camping in generally tepid weather, this is a good choice to consider for a stove.
Butane comes in disposable tanks.
This should only be used as a last resort. Gasoline is very noxious, puts out a lot of soot and does not burn efficiently. Cook your food with a lid on it to help prevent toxic soot from getting into your food. In extreme cold it can be hard to get a stove powered by gasoline to stay burning. Because it is a liquid, the stove it burns will have to come with a pump to keep the fuel pressurized.