Make sure it's empty! Lol then get a hammer and a bit of bar and just keep knocking the valve anti clockwise till it unscrews, then turn it upside down (gas is heavier than air) for a few hours, then I turn it right way round and fill it with water to force any air/gas out and leave it full for a day or 2, then empty and cut mate. They still smell tho so go in gently lol I've not blown up yet but I've only done 2 and that's how I did them. Heliums fine tho, and there in ideal camping size