Christopher Tidy wrote:


My plan was to take an "officially empty" cylinder out into our field
(we have no neighbours nearby) on a cool day, make sure it was away from
any sources of ignition and slowly open the valve to vent the propane to
the atmosphere. When the propane inside was at atmospheric pressure, I
intended to remove the valve and fill the tank with water from a hose to
expel the remaining propane. Not having removed a tank valve, I'm not
sure how easy it would be to fill the tank with water, but it seems like
a neat way to remove all the remaining propane. What do you think? I'd
be interested to hear your views.



When I did this, I opened the fill vent, opened the main valve and
then held a running hose against the main valve fitting until water
came out the vent.
jk