Cast Iron Rust

some rust spots are normal if it has gotten wet. They way to properly treat the pan is to wash it then dry it with a towel. To continue to dry it set it on the stove and heat the pan until all the water is evaporated. At this point I use a light coat of cooking spray and a paper towel to coat the pan. You want it to look shiny but not oily. For storage I would recommend hanging it on a wall with a hook or in an up side down position so moister will not settle on the part you cook with.

Keep it. Steel wool the rust. Once re-seasoned it will be fine.

Just scour it off and season. It should be fine. Several years ago I was given a cast iron dutch oven so badly rusted my first inclination was to throw it away but with a lot of TLC, elbow grease and a nice hot bonfire it's as good as new and has served me well for many years now. While this is not your situation, I'm using it to illustrate just how bad a cast iron object has to be rusted to rendered useless.

Seasoning Steps

1. For crusty cast ironware that you inherited or picked up at a garage sale: Your cookware may have some combination of rust and thick crackly black crud. It can be restored fairly easily to good as new condition! First place the cookware in a self-cleaning oven and run one cycle OR place in a campfire or directly on a hot charcoal fire for 1/2 hour, until dull red. The crust will be flaking, falling and turning to white ash. Then, after allowing to cool a bit to avoid cracking your cast iron,use the following steps. If you have more rust than crust, try using steel wool to sand it off.
2. Wash your cast iron cookware with warm water and soap using a scouring pad. If you have purchased your cast iron cookware as new then it will be coated in oil or a similar coating to prevent rust. This will need to be removed before seasoning so this step is essential.
3. Dry the cookware thoroughly, it helps to put the pan in the oven for a few minutes to make sure it's really dry. Oil needs to be able to soak into the metal for a good seasoning and oil and water don't mix.
4. Coat the pot or pan inside and out with lard, Crisco, bacon fat, or corn oil. Ensure that the lid is also coated.
5. Place both the lid and the pot or pan upside down in your oven at 300F for at least an hour to bake on a "seasoning" that protects the pan from rust and provides a stick-resistant surface.
6. For best results repeat steps three and four and five.
7. Ongoing care: Every time you wash your pan, you must season it. Place it on the stove and pour in about 3/4 tsp. corn oil or other cooking fat. Wad up a paper towel and spread the oil across the cooking surface, any bare iron surfaces, and the bottom of the pan. Turn on the burner and heat until smoke starts to appear. Cover pan and turn heat off.

I have cast iron items and they have had lots of rust. If the finish is not damaged then it can be okay. I googled cleaning cast iron and found one methods I use all the time. I put regular veggie oil and salt on the pan and rub it. It doesn't scratch the surface but dissolves and cleans the rust. If it is still there then you may just need to look further and find the right way that works for you.

I had a griddle that had never been taken care of correctly, it was given to me, and my MIL had it sand blasted. I coated it in veggie oil and did the whole baking thing, it still looks nice and I do rinse it off with water to clean it. I just heat it to dry it on a burner then put some oil on a paper towel piece and rub it down then store it in the stove. (Don't burn your hand)

If the pan is really rusty all over, throw it in a fire and use a wire brush on it after you see the rust starting to come off. No pan is unusable...they can all be salvaged...It depends on how much you want to work...
If your pan just has a few rust spots, just clean them out, and re-season it. When you store them, put a paper towel in them. The rust will come back, but as long as you stay on top of it, it shouldn't get much worse...
Good luck!
We really enjoy cooking with the dutch ovens, and using cast iron fry pans...We belong to a group that does this...Cornbread is the best cooked in cast iron..

The rust is on the surface of the pan, so when you scour it off, the rust is gone. If it's really really badly rusted, then the rust goes all the way through the metal, and if you got rid of the rust, you would have a hole in the pan. The rust won't reappear unless you neglect the pan.

I'm not sure either how much rust is too much. But I'm thinking, you really only need to use a steel wool cleaning pad to remove it. If it's not been seasoned, then do that. If it needs some kind of oil at that time, that will protect it from future rust. I can't imagine throwing it away. But cast iron that is used regularly will develop its own protection and won't have time to rust again.

The advice you've received already is great. I'll add that some people never use soap and water on their cast iron, though I do. But after each use and washing, I do dry it carefully to prevent rust. Unless I've accidentally overheated it, the seasoning carries through nicely even with a washing. Add new cooking oil at the beginning of the next use, and you'll probably be fine (even without making the oil smoke).

One of my favorite cast iron pans is a large two burner pancake griddle. I found it sitting on a stump where someone had left it, and it was totally rusted. I took it home and scrubbed it well then dried it. I then spread cooking oil over all the surfaces and baked it in the oven for several hours to let the oil get into all the 'pores' of the metal. It has worked just fine for me for over twenty years. Yes, if you wash cast iron, it may develop some rust spots, but they are easy to overcome.