The Eastern Shoshone made metal points out of iron from
cooking pots.  These are rarely found now in Wyoming as
the inferior metal degrades so easily.  I used to have a
reference for metal points, but my house burned, taking my
books with it.  The author's name has left my head, but I
think the title was something like Tools and Trappings of the
Northern Plains Indians.  Maybe the publisher was Univ of
Nebraska - Bison Books.  The book also had trade knives in
it.