Why does my cast iron skillet leave a black residue on foods?

I think it is tiny, burnt food particles trapped in the pores of the skillet. Seasoning theoretically creates a smooth, non-stick barrier between the metal and your food, but if you're washing your skillet with soap, the effects will only be temporary. read more

Even seasoned cookware produce black residue over the food cooked in cast iron skillet, if the skillet has been cleaned after previous cooking with soap and rigorous brushing with hard brush or steel wool. It can be avoided by apply soap and soft sponge with warm water for cleaning such utensils. read more