1st Timer charging from cylinder

[Dave in Texas]

I was given a partial cylinder DuPont R12(30lb tank). There wasn't much left in it so I thought I'd use as much as I could. Cylinder weighed 8.55lbs when I started and when it reached 5.96lbs there was no more liquid in tank. 60oz needed for full charge. Looks like I got 36oz in? Wasn't sure whether to keep compressor running or not, so I shut it down.
When there is no more liquid in a tank, what is the correct thing to do??
There is pressure in the tank but the compressor wasn't taking in any gas and weight on scale was not changing. Just unsure about dealing with empty tank...learning.
Thanks
Dave

[GM Tech]

If tank has 80 psi and compressor is running and low side is 30 psi, then it will draw in refrigerant, turn tank upside down will help- warming tank will also help. when empty the tank should measure same as low side was when running...

[Dave in Texas]

If tank has 80 psi and compressor is running and low side is 30 psi, then it will draw in refrigerant, turn tank upside down will help- warming tank will also help. when empty the tank should measure same as low side was when running...

Thank you for your response. Checked tank psi.....33psi. If my math is correct I still need to install 1lb+Xoz to get to full 60oz charge?
I appreciate your help.

[mk378]

There's only a couple oz of gas left in that tank. You will need to procure more R-12. Empty tanks should be pulled into a vacuum using a recovery machine, then punch a hole in the tank and recycle the metal. The refrigerant in the recovery cylinder can be used.

[Dave in Texas]

There's only a couple oz of gas left in that tank. You will need to procure more R-12. Empty tanks should be pulled into a vacuum using a recovery machine, then punch a hole in the tank and recycle the metal. The refrigerant in the recovery cylinder can be used.

I will need to procure more R12....thanks