How to use phone parts during survival

Cutting tool from the phone Spear parts

Each cell phone also had a circuit board.I used the circuit board from a smartphone to make two very useful item to a survivor.I noticed that when i abraded the edge of the circuit board against a smooth rock it actually ground down to a fairly decent cutting edge.it used half of the circuit board to make a useful cutting tool which i used to gather and cut some natural bark cordage and also scrape a pile of very fine fire tinder shaving from a dried mullein stalk.Both of these item are incredibly useful to a survivor. 

Then shape the other half of the circuit board into an arrowhead spear point.