Any suggestions on storing a 1/2 to 2/3 full can of R12? I'm guessing the can tap will leak a tiny amount, especially since the top of the ancient can had some surface rust (the price tag on the can says $2.35). I have it sitting in my bedside beverage chiller. How long before it all evaporates out?

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280