If the chip is no longer in use at a casino, it is obsolete. I would extend this definition for those locations where you can buy chips at the cage to: If you cannot get the chip at the cage, it is obsolete.

This definition does not apply to Limited Edition chips that were never intended to be used on the tables. Some LE's are obsolete on the same day they are issued. I do not consider LE's current or obsolete, they are just LE's.