The word from Wisconsin was that the tribal folks took a 55 gallon drum, shot holes in it so it would be abrasive, then had it turning so it ground up the chips. When this didn't work fast enough, they were dumped in the lake. Some managed to just get lost in the back of the van, and that's why some uncanceled obsoletes are in collectors hands. This would be the Rainbow Casino $5 Chipcos. Might be the Majestic Pines chips as well. I don't know the story on the RCC, Red Cliff Casino or Jenna chips that escaped.

Left "ZAB" Castaways, LV
Middle Overprinted Grand Casino: Hinkley, MN
Right Notched Chipco Caesars Tahoe NCV