Contrary to popular belief a Lid is not an ounce of weed. The coffee cans had a key like a sardine can and the Lid would be wound off the can. The Lid used to measure usually contained about 4 fingers of pot. People at that time didn't have a triple scale to weight pot.
Maryjane sold me a Lid of Acapulco Gold and it's one finger short of a full bag.