If it is only light patches of rust use cooking oil and a rag and a fair bit of effort, if it is more than that then wire wool (but gently) but cooking oil first as it softens the abrasive effect somewhat
Take potato, and split it. Add table salt to rusty spot, and start rubbing it with potato. Once finished, wipe with hig smoke point oil or lard, and season it.Good oil is sunseed oil...Edit. Youtube there is guy called culinary fanatic, whom gives great tips on cast iron.
How's the pot coming along mate?
Looking good. Now cook some bacon in it just to nibble on and to add some extra fat into this beauty. Then make a "campfire" chile with meat and a cornbread topping. Step one, build a fire. Use char cloth ( anyone can use a lighter ) and your Moras to process wood. Step two, find a recipe you like. There are so many to choose from. Step three, get out your Whisperlite and make a pot of coffee or tea.Step four, Use your Opinel to cut up all the ingredients.Step five, Sit back and enjoy with hot cup of coffee or tea.