The casino was responsible for culling out the "foreign" tokens. Unless they could redeem them back to the actual casino, they were then stuck with them and supposedly was required to destroy them. Selling from the cage was not allowed, but it did happen.

BTW - "Foreign" just means tokens not issued from the casino. Tokens from the Riviera are "foreign" to the Mint, or Thunderbird, etc.

Most tokens would work in most coin accepters, however, some casinos had tokens that had a slightly different weight or thickness dimension, which the coin accepter could be calibrated to make rejections of foeriegn tokens. Just before tokens went completly away, the token manufacturers did come up with security attributes that screened for valid tokens.

Jim