Soap Dispenser for Washing Machine

This is a tool that was hung on the rim of the early hand cranked clothes washing machine. You placed a chunk of home made lye soap in the top of the tool, exposing it to the cheese grater like rasp. While pressing the lid down on top of the soap, you would crank the handle, thereby grinding soap flakes which funneled directly into the wash water as the crank was turned.
I remember my Mother getting the same results by slicing soap flakes off of the old Fells Naptha soap bars with a pen knife during Monday washing chores.