OP:
Find out where scrap metal would be taken in your area for disposal.
Take the pieces that you can there.
Ask the proprietor: Who brings larger pieces in to them that would make pickups at a (residential) address?
Call ‘em!
...I suppose you could drop the “take pieces there” part of you have no pieces small enough. Find out who takes. Call em and ask who can be contracted to make pickups.