If cast iron is left in the sink to soak, put in the dishwasher, or allowed to air dry, it will rust. It can also happen when you store your cookware in moisture-prone environments, such as a cabinet near a dishwasher, an open cabinet in a humid location, or stored outside.
The surface is usually the first place where rust appears. If you check the surface of your cast iron skillet, you may notice small dark brown or black spots. These are likely rust spots and may indicate that your cast iron is no longer safe to use.
Cast iron is porous, meaning that long exposure to water can cause it to soak up the moisture and eventually rust.
Cast iron pans can leach a sizeable amount of iron into your food, exceeding dietary intake in some cases. Acidic foods will contribute to much more leaching while an old, heavily-seasoned pan will leach much less iron than a newer one.
Sticking your skillet into a roaring fire might seem like a good way to heat it up in a hurry, but overheating or uneven heating can cause your skillet to take on a permanent warp, or even crack.
With proper care cast iron cookware can withstand a lifetime of use.
Cast iron is not made to withstand harsh chemicals and cleaners that can strip your seasoning and ruin the cast iron. Baking soda and vinegar seem natural enough but they will also agitate and remove seasoning on your pan.
Cast iron seasoning is a layer of carbonized oil.
It may take a little extra care, but a well-seasoned cast iron pan will last for generations.
When is too much too much? Although it seems odd, it is technically possible to over-season a skillet. Too much oil baked into the cast iron will cause it to polymerize unevenly and eventually will cause the surface of the skillet to flake.
Cast-iron skillets are naturally prone to rust. But even if it has turned bright orange, the pot absolutely can be fixed. (Even if you snag an old, rusty skillet at the flea market, that orange will come off!) It only takes a few simple steps to have your rusted cast iron looking brand-new.
In addition, by using cast iron with your everyday cooking, you are not only getting more iron and fewer chemicals in your diet, but you're also learning how to cook with time-tested cooking gear.
The reason given for this rule is that if you were to use soap, it would strip the cast iron of its “seasoning.” Seasoning is a layer of polymerized oil that's baked into all cast-iron cookware. It's what gives a cast-iron skillet a non-stick (really more like an “easy-release”) surface.
Should I Oil My Cast Iron After Every Use? After each use, to get the most out of your cast-iron skillet, it is best practice to apply a thin layer of oil on the surface. Regularly oiling your cast iron skillet will provide a protective layer to the surface and help keep it from rusting.
"You can't clean cast-iron the same way you clean stainless steel," kitchen expert and author of "Kitchen Matters," Pamela Salzman says. "It's very porous," Rach adds. "That flavor will stay in there and literally bake into the pan."
Yes, extreme temperatures can strip everything off a cast iron skillet but that's not usually an issue in our home kitchens (unless you set your oven on clean cycle). Cast iron skillets can take heat that exceeds the smoke point of most oils we use for cooking and “they like it!”
The acidity of tomatoes makes them challenging to cook in cast iron. Anyone who's ever eaten a tomato or cooked with tomatoes can verify that this fruit is quite acidic. As it happens, the tomato's acidity is precisely why doesn't work well with cast-iron cookware, especially for long cooking stretches.
Even though a rusted cast-iron pan doesn't necessarily present a health concern, it's still not recommended that you cook on it. The rust might add an unpleasant metallic flavor to your food. Plus, it makes using the skillet much more difficult.
The black residue on a cast iron skillet isn't harmful; it's just a part of cooking with a cast iron pan. A black seasoned coating shouldn't rub off easily or affect the food, as it should form a useful non-stick surface for cooking. If residue starts to build up, however, this can affect your cooking.
Clean cast-iron skillet after every use
Wipe interior surface of still-warm skillet with paper towels to remove any excess food and oil. Rinse under hot running water, scrubbing with nonmetal brush or nonabrasive scrub pad to remove any traces of food. (Use small amount of soap if you like; rinse well.)
Can I use steel wool or a metal scrubber to clean my cast iron pan? No! We recommend using a pan scraper or the Lodge Chainmail Scrubber to remove any stuck-on residue.
Don't ever store food in a cast-iron skillet
Additionally, although the idea of getting iron toxicity overload from cooking in cast iron pans has been mostly debunked, (via Livestrong) any food sitting in the pan for a prolonged period of time can develop an off, metallic flavor.