Interesting trivia: there are more Catholic Churches in Las Vegas than casinos.
But it is Las Vegas, and donation plates in all these Churches often include casino chips along with the cash.
This presents an issue, of course, since these chips aren't spendable outside of the specific casino they came from.
The Churches, along with a Franciscan Monestary in suburban Henderson, developed a plan to redeem these chips. The Monestary collects all the chips once a week, sorts them, and in return for a "vig" (a percentage), cashes these chips in at the various casinos around town. They then give the cash, minus the vig, back to the Churches.
Only certain, senior members of the Monestary are trusted with this duty.
Collectively they're known as the chip monks.