[CarGuy]

I will not do it for the same reason given to not use empty freon tanks for air tanks. These bottles are not strong enough to refill. Every time a tank is pressurized it expands a little then when pressure is released it contracts. This causes the metal to flex and continued flexing of metal causes it to weaken. It may work most of the time but it only takes one failure to cause a bad day/month/year/life.