I play a bunch of Middle Eastern lute-type instruments which traditionally used a feather plectrum. The material currently traditional in Turkey and Palestine is a strip cut from a plastic bottle or jerrycan, but I prefer the plastic strapping used to package building materials - there are several different types, it's worth having a few on hand to give you different weights and flexibilities. See my cumbus page:

http://www.purr.demon.co.uk/jack/Music/Cumbus/cumbus.html