Horseshoe Chips = off the tables, no longer in play.

The AC chips are obsolete, but still valid checks from the casino. They are also NLIP

If everyone wants to jump on this, assuming that the casino won't ever open, it's obsolete.

If it's no longer used and out of date, it's obsolete.

Since we don't know if the casino will re-open or if there will be redemption or just a shutdown and all chips voided, I'd say wait and see.

If they re-open tomorrow, is someone going to say in an auction, "the once absolete Horseshoe chip..."

Say, can we do this same debate again next month?

The problem lies in the minor details and variables, obsolete doesn't lend itself to a hard and fast definition. But out of date, no longer used, works for me. Even if you can cash them in... Even if they may come back into use, which we can't predict. Even when the casino is closed, but may re-open.