At least some share of the chips is of an earthen material similar to sand, chalk, and clay much like that found in cat litter. The process used to make these chips is a commerce secret, and varies barely by producer, most being relatively costly and time-consuming per chip. Then every chip receives a mid-inlay if desired, and is placed in a particular mildew that compresses the chip, therefore the term compression molded chips. The stress of the compression and the warmth that is added varies from manufacturer to manufacturer. While some casinos which put in the receipt system had kept the $1 tokens around for use as $1 chips, most other casinos utilizing the receipts had simply scrapped the tokens entirely. Most casinos utilizing receipts have automated machines at which clients could redeem receipts, eliminating the need for coin counting windows and reducing labor prices.