If You See Black Residue on Your Cast-Iron Skillet, This Is What It Means

The black residue on a cast-iron pan isn't harmful, but it's not appealing either. Here's how to clean it up.

Taste of Home editors love a good cast-iron skillet (especially when it’s budget-friendly cast iron). You can never have enough—I have three myself! But when I cook with a cast-iron pan, what are those black specks that sometimes come off in my food? I did some research and found out how to fix cast iron black residue.

What Causes Black Residue on Cast Iron?

Carbon Deposits

First, the black specks you see coming off into your food are not harmful. They are most likely carbon deposits. This happens due to overheating of fats and oils. Using an oil with a low smoke point will carbonize at high temperatures and cause residue from the pores of your pan to rub off onto your food. While unappealing, they won’t hurt you in such a small amount.

Don’t make these common cast iron cooking mistakes.

Burnt Food Particles

It can be difficult to properly clean your cast-iron skillet without removing the seasoning, so blackened bits of old food might be the reason you’re seeing flecks on your latest meal. Be thorough in your cleaning process—here are the products we trust to clean cast iron.

Residue on Brand-New Skillets

Your new skillet may be have been pre-seasoned to keep it from rusting in the store. This seasoning is not meant to last forever and can start to flake after the first few meals you cook. The oil or wax coating will start to disintegrate with high heat and will not hold up for long.

How to Remove the Residue

Use the Proper Oil

Make sure to use an oil with the proper smoke point for your food. Avoid overheating, and you’ll start to see the black specks on your food disappear.

Clean Your Cast Iron

You can use two methods to give cast iron a good scrub: salt or a stiff brush.

Pour a quarter cup of salt into your pan and use a flat-edged kitchen utensil to push the salt around the pan. The salt will begin to discolor as you scrub. Remove all grains from the pain to avoid corrosion, then apply a light coat of oil.

For a stiff brush, let your pan soak in water for about an hour. Scrub with your brush using a small amount of soap if necessary. Dry with a towel and set on high heat over the stove. Let all moisture evaporate, and then allow the pan to cool. Apply a light coat of oil.

Season Your Pan

Using cast iron means regular maintenance, aka seasoning your cast iron skillet. Fortunately, it’s an easier task than most people expect.

  • Clean off all residue (as described above)
  • Cover the entire surface with oil and remove excess with a paper towel
  • Place pan in the oven at 500°F (or as high as possible) for an hour
  • Turn off oven and allow pan to cool inside
  • Repeat as many as five times

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Melany Love
Having always wanted a career in writing, Melany couldn't have found a better place than Taste of Home to begin. When she's not scribbling in her notebook or working at her computer, she can be found experimenting with new recipes or relaxing with a book and her cats.