It varies as to what the makers put on the cast iron to deter rust during the crossing of the Pacific.
I used to see beeswax coatings., sort of like gooey bullet lube. Lacquer thinner was the only thing that was efficient in removing it. Had to be a little careful. The paint would remove easily with that stuff.
I'd put down a paper towel maybe half the size of a sheet of typing paper. Pour on a little lacquer thinner and let it soak for a minute or two. Wipe up the area with the wet paper towel and some dry towels. Repeat across the surface in need.