It will work, Chris Cade gave me and old rusty cast iron pot at the Classic a few years back, he though it was to far gone. I filled with lard and let it slow cook all day on the fire, then cleaned it out and rubbed the outside good and done it again, it took 2 or 3 times but came out black and slick and ready to use. He was amazed the next time he came and I showed it to him, I think he wished he hadn't given it to me, it came out of an old shed at his Grand daddy's place. Guess I should give it back if he shows up again.
I have always got a fire going if I am at the cabin so it's no trouble for me to cook one all day If need be.
Pappy