Roulette chips are unique (vs. other games) by not having denominations printed on them.
(Some non-USA roulette chips have denominations, but I'm speaking of US roulettes.)

That's why I never harvest roulettes -- with one exception. I did get the Paris Las Vegas "jeton" roulettes from the European style table when it was operating. But those had denominations. (In addition, some members have successfully asked the roulette pit boss for a set, and if he says yes, then no problem. The "grey area" is when roulettes are pocketed without permission... even though the player has no intention of re-introducing the chips later for personal gain.

The subject of roulette harvesting has gone round-and-round (no pun intended), and I'm not here to re-hash the various arguments, pro & con.
Just my personal decision on the subject.

Since you appear to be a newer member, just thought I'd share some of the history regarding roulette harvesting.