I'm sorry guys, I guess I should have been more specific. I know about putting them back in the container after their initial few uses to freshen them back up -- what I'm talking about is aftery they're old... like a couple years old and have been used several times and have no scent left on either the wafer or in the container.

That's the situation I was referring to: I've got tons of these things sitting around and have always been reluctant to throw them away thinking someone could come along and tell me a way to get them to absorb their cover scent again. Probably not possible, and would probably be cheaper/easier to just buy new ones, which is what I have always done.