I was recently watching one of those prison specials on MSNBC and saw the most interesting weapon made from a non-weapon. They made shanks out of cellophane. They saved them from their commissary packages. They cut down the edges of the packages until they had flat sheets of it. Then they stacked the cellophane sheets several layers thick, and rolled them up and held them rolled with a rubberband. Then they’d start a fire, and heat it, then quench it in some cold water, and repeat over and over until it was hardened and melted to the shape they wanted. Then they could sharpen the point on the cement.

They also made zip guns, using tightly rolled up paper for the barrel several layers thick. The propellant was ground up matches, with loose nuts, bolts, nails, rocks and stuff for the projectiles.

Then there’s the simpler stuff like shanks from bedsprings, toothbrush weapons (shank or melted with razor blades attached, etc.) etc…

This PDF file would interest you if you haven’t seen it. FBI GUIDE TO CONCEALABLE WEAPONS 2003