Back in ancient times flashlight cells of different sizes didn't have metal jackets, but were in a printed cardboard sleeve that you could push the cell out of! My Dad gave me a black and chrome EverReady penlight when I was 4 years old and of course I left the battery of two AA cells in it and they leaked leaving the flashlight plugged. At that time before 1950 or so RayOVac was I believe the only "sealed in steel" cell and guaranteed leakproof or they'd replace your flashlight. I think Burgess D cells may have been also in steel, when I got into radio in the early fifties. I remember seeing lots of the older carbon zinc cells leaking, but then ran across this no-leak anomaly which sits on my desk.
