Cook's Illustrated
says that fat used to fry protein...fish, chicken, chicken fried steak should only be used once.
However, fat used to fry carbs, like french fried potatoes or doughnuts may be strained and used up to four times.
I also had a great aunt who had one of these, but it went to her younger daughter. I got a Limoges demitasse instead.
Lawrence/Maytagbear