Expansion valve testable?

[zenuff]

Is their a way to test the expansion valve after it has been removed from the car. I would like to reuse this one if possible. What can I look for to tell if it's bad.

[zenuff]

Are expansion valves universal for R12 or Freeze 12 or 134A or whatever or is their a specific on for each?

[zenuff]

I was thinking of putting it in the freezer for a little while. It looks like one side of it is closed as it sits. The small side of it, seems to be the opening with restricter in it.