Because of open fire restrictions in many national parks, state forests or municipal backcountry lands, butane-powered stoves are useful camping tools. Compressed butane, most often in metal cylinders, provides a controlled flame for cooking and heating water. Disposing of butane left in canisters after a trip becomes a tricky issue. Recent studies show butane left in landfills raises carcinogen levels -- making it hazardous material. Therefore, users must dispose of butane remnants properly. Most city and municipal recycling centres accept old butane canisters.
Remove as much as possible of the butane from the canister by attaching it to the stove, firing it up and letting it burn out. Due to the compression methods used with the canisters, it is not possible to burn out all of the fuel. But remove as much as you can, since this also reduces pressure in the canister.
Use a specialised tool, such as the Jetboil Crunchit, to puncture and then compress the canister.
Place the butane canister into a dedicated recycling bag for such canisters, old butane lights and other containers with residual butane left inside.
Dispose of the now drained and decompressed canisters at a certified recycling centre. Recycling centre lists are available at Earth101.com.