The Yellowstone Specialty Company was headquartered in Salt Lake City, UT and had a branch in Idaho Falls, ID. The Idaho branch is still in operation as operating pinball machines. Possibly other branches as well, although I haven't found any. It was listed in several directories as a manufacturer. I believe the company operated amusement machines of several types, probably including slot machines, in UT, ID, MT, & WY. The earliest directory listing I've found for the company in ID is 1919. There are denominations known from 5¢ up through $20, leading me to believe that the higher denominations were used somehow as counters. One possible scenario - a route serviceman would go into a tavern or wherever one of their machines was placed, open it up, count the cash, and give the proprietor tokens equalling the amount of the take. Then the proprietor would exchange them somehow through the Yellowstone Specialty company accounting department for his share of the value. They may have had some sort of sliding scale arrangement like "if the machine takes in $2.50, you get $1.25 and we get $1.25." This is purely speculation on my part. The higher denomination tokens could well have been payouts for real jackpots, and the customer could have exchanged them for face value in trade at the tavern where the machine was located. Or lost them in WY...
John in ID