That spot in the middle of your cast iron is usually caused by uneven heat, too much oil, or pan warping. Cooking and cleaning habits can also create noticeable light or dark marks in the exact center of the skillet.
If you see some raised, splotchy residue on your skillet, which often looks like a spiderweb or spotted pattern, this is most likely some oil residue. This sticky situation can occur when you season your pan with a little too much oil, or if some oil hasn't fully polymerized and turned into seasoning yet.
This Is When to Throw Away a Cast Iron Skillet
This is just a sign of excess oil built up on your cast iron. Place your skillet upside down on the top rack of the oven to bake for one hour at 450-500°F. This is also a good time for a refresher on your cleanup routine! After you cook, wash your cast iron in warm, soapy water.
Neither is objectively "better"—they just excel at different things and come down to personal preference.
Cast iron skillets can last a lifetime—and even last for generations when cared for properly. Because they are built from a single, durable piece of metal, they do not wear out like traditional non-stick pans. Even if a pan develops rust or loses its seasoning, it can almost always be stripped down and restored.
Yes, you can absolutely use Dawn dish soap on cast iron.
Symptoms of Teflon flu or polymer fume fever include chills, fever, fatigue, headache, body aches, and occasional chest tightness and airway irritation. People with underlying lung diseases such as asthma are more likely to develop respiratory symptoms.
Put the oiled pan in a preheated 450°F (230°C) oven, and leave it there for 30 minutes. It may get a little smoky, so keep your kitchen well ventilated. It's during this time that the oil will polymerize and form the first of several hard, plastic-like coatings you'll be laying down.
To get stains out of a cast iron skillet, start by scrubbing a paste of coarse kosher salt and water with a stiff brush or chainmail. For stubborn, burnt-on spots, simmer 1/4 cup baking soda and 1 cup water for 10 minutes, then scrub and re-season with oil.
According to the U.S. Environmental Protection Agency (EPA), ingesting rust in small amounts will not harm your health (unless you have a rare disease called hemochromatosis, which causes your internal organs to retain iron).
If it's solid and intact, you can absolutelyrestore skillet surfaces, even if they look terrible.
No, it is not bad. Modern, mild dish soaps are completely safe to use. The old "no soap" rule comes from decades ago when soaps contained harsh lye, which stripped the skillet's seasoning. Today's gentle dish soaps simply cut through grease without harming the baked-on, nonstick layer.
Your cast iron is clean when no food residue remains, the surface is dry to the touch, and there is no sticky or tacky residue. A clean pan can be maintained with three basic steps: washing, drying, and lightly oiling.
A cast iron skillet is ruined primarily by rust from soaking or improper drying, warping from extreme thermal shock (like cold water on a hot pan), or cracking if dropped. While most seasoning issues are reversible, letting rust cause deep pitting, or fracturing the iron, destroys the cookware permanently.
Detergents aren't made with lye, so can't be soap. Either way you still shouldn't use soap with cast iron, but can use detergents, though there is no reason to do so. You can easily clean well maintained cast iron without it.
Any food-safe cooking oil or shortening will work, but our Test Kitchen experts prefer vegetable oil or canola oil. WHAT'S THIS DARK RESIDUE I SEE WHEN I CLEAN MY CAST IRON? Occasionally, you may notice some dark residue on your paper towel or cloth while cleaning it.
The healthiest pans to cook with are made from cast iron, carbon steel, stainless steel, or pure ceramic. These materials are free from toxic synthetic coatings (like PFAS and Teflon) and will not leach harmful chemicals or microplastics into your food when heated.
You should generally avoid cooking highly acidic foods (like tomatoes or citrus) and sticky foods (like delicate eggs or thin fish) in new cast iron. These ingredients can leach iron into your food, strip the pan's seasoning, and stick aggressively to the cooking surface.
Cast Iron Cons
Unfortunately, iron is prone to rusting and long-term effects will harm the material. Frequent exposure to moisture will only accelerate the process. Cast iron is a very heavy material which makes working with it very difficult.
To quickly tell if your cast iron is properly seasoned, look for a smooth, matte-to-slightly-shiny black surface and perform the water test: pour a little water into the pan—if it beads up and rolls off easily, your seasoning is solid.
Before the turn of the century, newly poured cast iron would sit in the molds for two days or more before being tumbled and polished for a full 24 hours. This resulted in a glass-smooth cooking surface.
To strip cast iron back to bare metal, the easiest and most common approach is a 3-step process: remove stubborn carbon build-up with a lye bath or oven cleaner, dissolve rust with a vinegar soak, and scrub vigorously. Once you reach bare metal, you must re-season it immediately.