We saw several of these machines for cracking cashew nuts one-at-a-time. The nut is placed carefully on the lower u-shaped anvil and then the cracker is activated by a foot pedal. The shell is 1/8 inches thick and contains a caustic oily liquid which can cause skin irritation and even severe burns on contact. The machine operators wear protective clothing and rubber gloves to protect themselves from the liquid inside the shells. Don't collect and attempt to open cashews yourself!