How to Clean Soot Stains (Discoloration) on the Outside of a Pot

The dark, greasy-looking discoloration on the outside of a pot is caused by soot and burnt-oil residue left on the metal by the flame. It can generally be cleaned by scrubbing with a baking soda and water paste, with vinegar optionally drizzled over it, or by soaking the pot in hot, soapy water for a while and then scrubbing it.

Why do soot stains form?
When a stove flame extends beyond the bottom of a pot, carbon particles produced during combustion stick to the metal surface and gradually leave a thin, blackish layer. This buildup does not form all at once; it accumulates in layers as the pot is used on the stove repeatedly, so it can become noticeable within a few months even on a new pot. A flame larger than the pot’s base—that is, one extending beyond the sides of the pot—is the most common cause of this buildup. Adjusting the burner power to the size of the pot significantly reduces soot formation.

How can it be cleaned?
A thick paste made by mixing baking soda with a small amount of water can be spread over the discolored surface, left for 15–20 minutes, and then scrubbed in circular motions with a sponge or soft brush; baking soda’s mildly abrasive texture lifts soot without damaging the metal. For stubborn stains, drizzling a little vinegar over the baking soda helps loosen the dirt through the resulting fizz. For heavier discoloration, the pot can be soaked for about half an hour in a large container filled with hot water and dish soap, then scrubbed. Soaking softens oil and soot buildup and makes cleaning easier. Abrasive materials such as steel wool should be used carefully, especially on surfaces other than stainless steel, because they can leave scratches.

Can discoloration be prevented?
Keeping the stove flame within the base of the pot is the most effective way to prevent soot buildup; even with large pots, the flame should not extend beyond the sides. Wiping the pot immediately after cooking, while the stain is still fresh, makes it easier to remove the dirt before lasting discoloration forms. Occasionally wiping the outside of the pot with a thin layer of cooking oil and drying it may also create a protective layer for some users, reducing soot’s direct adhesion to the metal to some extent.

Do all pot materials react the same way?
Stainless-steel pots are relatively resistant to soot stains and are generally not damaged by abrasive scrubbing materials. By contrast, abrasive materials can scratch aluminum or nonstick-coated pots, so only a soft sponge and mild abrasives such as baking soda should be used. On copper pots, exterior discoloration is generally caused by oxidation of the copper itself rather than soot and requires a different method, such as a lemon-and-salt mixture. Soot adheres relatively little to the enamel surface of enameled cast-iron pots, but stiff brushes can crack the enamel, so a soft sponge is preferred here too. Whatever the material, make sure the pot has cooled completely before cleaning, both for safety and effective cleaning; otherwise, a sudden temperature difference can even crack some materials.