what is the hole in the coke can lid for
Beverage can One variation was the press button can,[28] which featured two pre-cut buttons—one small and one large—in the top of the can sealed with a plastic membrane. These buttons were held closed by the outward pressure of the carbonated beverage. The consumer would open the can by depressing both buttons, which would result in two holes. The small hole would act as a vent to relieve internal pressure so the larger button could then be pressed down to create the hole used for drinking the beverage. Consumers could also easily cut themselves on the edges of the holes or get their fingers stuck.