Please be careful in your definition of "no longer used." Many LEs are NEVER "used" in the casino. Are these chips obsolete the day they are issued? Even if they appear on the tables, the fact you cannot find one on any given day does not mean they are obsolete. I believe a cash value chip officially becomes obsolete when it is no longer redeemable. When a casino removes all of its table games or closes its doors, or completely replaces a rack with a different rack (as recently done at Boomtown Verdi and Nugget Sparks), the chips can reasonably be classified as obsolete even if they are still redeemable.

This is even trickier with NCVs. As long as a casino is open, we can rarely be sure an NCV with the casino's name won't be used for some purpose at the casino. We can safely call them obsolete if they've been destroyed (hard to know that most of the time), sold in quantity to collectors, or the casino is closed.

Roulettes should be the easiest. When a casino closes, eliminates the roulette tables, or replaces old beat-up chips with new ones, the old ones are obsolete.

And remember, as long as the chips are in the vault, there is the risk that what we thought was obsolete isn't any more. I can live with that.