you can't actually throw anything out, though i guess i could see why you might want to do that. iron rods you can dig up in several places, but maybe the most identifiable are the two 'rust desert' sectors just north and south of brulvundojn's lair.
cables... so this is actually something i've patched in the current (still-unreleased) version, but currently you can only dig up frayed cables in one place: those same two rust desert sectors, randomly mixed in with a bunch of other stuff. you can dig up ancient resin at the tree or at either of the two canyon locations. you can dig up worn wires a bunch of places, but most easily from directly south of yapu. using those you can craft cables in your workshop.
(there's not a lot of guidance for any of these and probably in a later version i'd want to add people telling you about digging locations for various items, or track which things you've dug up where and tell you, or something like that.)