removing old grease coating -- spray with oven cleaner, put in plastic bag for 1-2 days, scrub with brass brush, repeat if necessary or, cover with 1.5 gal water mixed with 1 can lye in a plastic container and soak for 5 days, scrub with brass brush
dissolve crusted rust -- soak in equal parts vinegar and water (do not soak longer than overnight)
season -- warm in oven a few minutes, apply a little fat, warm in oven at 225 deg for 30 min, wipe out pooled fat, warm for another 30 min
clean -- boil water in pan, soak several minutes, discard water, wipe dry with paper towel, wet surface with fat