I was recently researching what to do with an empty small butane canister (the kind used for portable gas stoves - same size/shape/wall thickness as a can of sp

I was recently researching what to do with an empty small butane canister (the kind used for portable gas stoves - same size/shape/wall thickness as a can of spraypaint). According to the municipal waste site for my city of just over 1 million, I can't put it out for any sort of collection, and I can't bring it back to the stores that sell them, I can't even take it to the landfill facility itself! The only option is some once-every-few-months single day events held in random far-flung parts of the city. While I'm responsible enough to hang on to it and dispose of it properly, I expect most people just chuck the empty (or almost-empty) canisters in the trash - causing exactly the same kind of fire risk you're talking about.