If, as you say, it's not rusted, what makes it look "pretty rough?"
If it just needs conditioning (assuming you mean seasoning?), +1 to what the guys said.
If you are talking about removal of the normal buildup of "stuff"
that comes with use, (reconditioning?) stick the pot in a self-cleaning oven and set the oven to clean! All the "stuff" will turn to ash and you will be down to the bare iron. Then season as was outlined.
I have done this to well used iron ware a few times and couldn't ask for better results. I have heard that there is a risk of warpage or cracking of the iron using this method but I haven't had any problem.
Nevertheless, I was a bit nervous when I stuck a 10 inch "Griswold" pan I found laying under a shed roof in the oven!