How much can you empty a 30lb drum?

[atikovi]

Drum weights about 10 pounds now so I guess there is 3 or 4 pounds of freon left if an empty one weighs 6 pounds. I understand I can't get it completely empty since the low side system pressure precludes that, but practically speaking, how much more can I get out of it? I do have a heater on it.

[Dougflas]

almost all of it. Place the drum in a pail of hot water and let the pressure increase.