Should be able to fold them in half to fit in the can, but otherwise a grinder with a cutoff wheel will do a better job at cutting them. Not without a god awful mess and stink though. I'd be more inclined to toss them in a tire shops tire pile.
Regarding your scrap metal stuff, nobody should be charging for that. The scrapers will come take it for free, or you can drop it off at a metal recycler yourself and get a couple bucks.