No, Insulated usually refers to copper wire.



You'll really need to make up your own mind about what's worth doing. Myself, I even decide it is or isn't depending on circumstances - and sometimes I throw stuff to the side to wait for a slack period.

Copper is red-ish; Brass is yellowish (for the most part). If unsure, file a piece until you get to clean, shiny part (I use a grinder). Pretty easy to tell then.