It appears there's no regulation that requires destruction of obsolete chips or chips from closed casinos in P.R. Somebody frequently gets the entire stock from the vault and they eventually get offered to a chip dealer. With thousands of each chip and maybe only a hundred or so active Caribbean collectors, most will never have appreciable value.

If you go back 20-30 years, there are some scarce chips. Not as scarce as AlbertR's book would lead you to believe, though [g].

I've paid $100+ for a number of older $1 chips from P.R.