I had this idea about using old propane torch bottles to cover up of pop up garden sprinklers. If the bottom were removed, the top placed downward it would form a housing for the sprinklers and a base of the flower, a little artistic stuff might be nice for a change. Anyway, my wife liked the idea but was afraid I would start something on fire or cause an explosion.

What is the best way to drain an old bottle ready for welding?