Step 1
Clamp the blade in a vise. Heat the area between the handle and the blade with a propane torch until it smokes, indicating the handle was attached using epoxy.
Step 2
Use a pair of locking pliers to grasp the handle while you wiggle it back and forth until the blade pulls free.
Step 3
Continue to heat the area between the blade and the handle of knives that don't smoke. Eventually the heat will melt the solder holding them together. Use locking pliers as you would for an epoxy-bonded handle, pull away the handle from the blade.
Step 4
Allow the blade and handle to cool back to room temperature for at least an hour.
Step 5
Place the handles on a hard surface such as a welding table or cement floor. Whack them on the surface several times along their entire length to loosen any investment inside. Use an ice pick or scratch awl to remove debris inside each knife handle.