Some casino's will cash their chips even after they change ownership IE: 4 Queens.

Casino's put out redemption notices. Once the time on the notice has expired, they don't have to redeem those chips that were on the redemption list.

I've found that in most cases, the cage personal are the last to know what's going on in their own casino.

The only way they become just collectors items, is if there was a redemption notice put out on them.

I hope this helps.

Ralph