I was once sent a $1 AC Playboy that was dark-gray. When I wrote the person thanking him I asked where did he keep the chip. He said in his tool box.

When I found the CAL-NEVA C&S chips, one green chip was stained with what looked like blood. I was offered 'double' the price I was selling all the others for... So, stained chips do have a value, I guess.