A while back I bought a Cadac, the type that uses screw in gas canisters. It has worked excellently till yesterday when the flames died. No problem, change the canister and all was well again. The problem is however the old canister still seems to have some liquid gas in it, which I guess means I can't just throw it in a dustbin. Should I vent all of the gas off before disposing of it, or even then would it be hazardous? What is the safest way to get rid of them, or am I over thinking things and lobbing it in a bin would be o k? Thanks.