1) They're never replaced. The chips you see in the casinos as the same chips in play when it opened 10-15 years ago.

2) They're never cleaned. Not sure if any Vegas casinos do this, but I know our MS casinos don't.

3) It's my belief that MS casinos have a larger blue-collar clientele than Vegas/AC casinos. I base this largely on the fact that MS and its surrounding states are much more rural and agricultural-based, and my observations after frequenting both MS and Vegas/AC casinos. Naturally a large percentage of the blue-collar clientelle visits the casinos after work while some of them still have the stains of their labor on their hands.

That's at least 3 contributing factors and there are possibly more.