A corkscrew is currently a useless item, and often considered as junk.
The corkscrew has no use, being added purely for the purpose of clutter, creating more realism for the player when looting.
Corkscrews can be found in kitchens and stores.
From newitems.txt (Project Zomboid directory/media/scripts/)
Type = Normal,
DisplayName = Corkscrew,
Icon = Corkscrew,
Weight = 0.1,
MetalValue = 5,