How do salvage yards and other companies dispose of freon and other CFCs?

In a cl that talks about the environment, I told my students that freon and other CFCs cannot be disposed of in the trash or released into the atmosphere. Rather, you are supposed to take trash like refrigerators and air conditioners to a licensed company that will recover and dispose of the freon appropriately. A student asked a good question-- what do these companies do with the freon? Presumably, somehow they somehow destroy it, but I don't know how. Thoughts?