Black stains developed on the bottom on stainless steel pot. These are coming back after cleaning the pot when I cook chicken. What are these, whether it is possible to get rid of these and it is it still safe to use this cooking pot?

Bottom of the cooking pot with stains

Here are the details.

When cooking soup, the water evaporated and the food badly burned in this pot. To clean it from this thick black layer of charcoal on the bottom of the pot, I had to boil this pot with salt, soap, and baking soda, apply Scotch-Brite, etc.

I noticed that some small pits (scratches) developed after that cleaning on the bottom of this pot. These pits were not black, but after I boiled chicken in this pot, these pits became black.

I cleaned the pot again - with soap (Ajax), vinegar, and tooth paste. When I boiled water in it, it was ok. However I boiled chicken in it, the black stains came back again.

Again, cleaned it thoroughly using toothpaste (nothing else worked) The stains did not come back after boiling water, boiling water with salt or pepper, but came back after boiling chicken.

What are these, is possible to get rid of these, and is it still safe to use this cooking pot (can I consume the food that was cooked in this pot)?

  • Does this answer your question? Cleaning brown/gray spots on overheated stainless steel stock pot
    – GdD
    Jun 17, 2022 at 8:28
  • 1
    @GdD I don't think this is a duplicate. The spots in the picture here aren't dirt spots as in the old question, they are pitting caused by the OP cleaning the pot aggressively
    – rumtscho
    Jun 17, 2022 at 12:41
  • @GdD, no your suggested question does not answer this question (I saw it before my posting). My biggest concern here that the black stains are coming back Jun 17, 2022 at 15:07
  • 1
    Are the spots holes through the stainless steel, and into some kind of base metal (aluminium, copper, ...) ?
    – Kingsley
    Jun 21, 2022 at 1:30
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    @user1234883 The cladding thickness varies by product, but it is likely less than 1 mm. The core may be Cu or Al for thermal mass, with a layer of carbon steel for strength. See here: therationalkitchen.com/best-stainless-steel-cookware-sets
    – Theodore
    Jun 25, 2022 at 21:17

1 Answer 1


So long as the marks aren't holes through the stainless (see comments above - probably not). I think re-passivating the stainless steel may fix the issue. Normally re-passivating stainless is done to treat rust.

Failing that, perhaps try a stronger acid like citric acid, or an acid-based cleaner. You've already tried vinegar - which is a relatively weak acid. (Note: vinegar should not damage 304/316 stainless steel, it's too weak). So I think trying something stronger may help.

Once the marks are gone, I would test-cook something of low-cost, and see if the spots return. If they do, perhaps it really is micro-holes down through into the base-layers.

And it's not pertinent to the question, but seems relevant: soaking stainless steel in strong alkaline solutions - especially bleach, will pit the metal. If you feel the need to wash stainless with bleach, be quick! No soaking.

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