I wanted a super small and lightweight sheath for the knife in my Pocket Survival Kit (PSK).
A Kydex sheath would likely take up way more real estate than this sheath.
Step 1: Cut Milk Jug
Cut the side out of a plastic milk jug.
Step 2: Cut Plastic
Cut the plastic to the shape of the knife blade.
Add some extra so the blade can be completely covered.
Step 3: Fold Tightly
Fold over the plastic as tightly as you can.
Step 4: Duct Tape
Tape the plastic shut as tightly as you can.