consider using Larry's definition above - at least as a "starting" point. I don't have the post in front of me, but his analogy along the line of:

"if the casino had it, would they sell it at face?"~~~~~ WORKS! It not only keeps the global "theory" and "implied relationship" of the item to "usefulness and value" accurate - but it applies the theory directly to chips in simple, easy language. Good expression of the correct application Larry!!

I like the idea of using a "list"... or listing examples like Larry did:

If a chip meets one or more of the following criteria, the chip could (not "would", not "IS" - leave room for exceptions and fickle casino policy ) ~ COULD ~ be considered "obsolete":

Casino out of business
New rack, old destroyed
Redemption period satisfied
Yadda yadda yadda

Webster DOES indicate "obsolete" can be used to describe things that haven't been in use for a significant period of time. I THINK the suggested time frame is:

"out of use for at least the last century"