- Prepare a solution of potassium thiocyanate (KCNS) and a solutionof iron (III) chloride (FeCl3)
- Moisten your hand with the solution of potassium thiocyanate
- Wait until your hand dries a little
- Soak a blunt knife or scissors in the iron (III) chloride solution
- Touch the fake weapon with your hand. When potassium thiocyanate and iron (III) chloride come into contact they react producing a dark red liquid that looks like blood.