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Feb 10, 2012 06:50 AM

White spots on tin (tin-lined copper)

I have a large tin-lined copper stock pot that I got a month or so ago. I have used it a few times to boil a chicken or to make stock, and the tin turned the expected blue-gray color. This week, I made a large batch of chicken soup that had a substantial amount of lemon juice in it. There are now white spots all over the inside of the pot. The tin is dark, with what looks like dozens of little white oxidation spots all over the inside. They have a very slight texture to them--if I slide my finger over a spot, I can feel that it is not as smooth as the other tin, but it does not wash off or scrape off (with a thumbnail).

Does anyone know what this is? Is it a problem? Should I do anything about it?



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  1. Hi, Jeremy:

    Sorry, I have no familiarity with this. You say there is texture to them--raised (bumps) or sunken (pits)? Regular in pattern, or does it look more like mottling?

    I think you're fine, but if it bothers you, try boiling a couple tablespoons of baking soda in it for 5-10 minutes. See if that helps.


    3 Replies
    1. re: kaleokahu

      Hi Kaleo,

      Thanks for the reply. It's hard to say if they are raised or pitted. The thumbnail catches on them just a bit. They almost have a 'chalky' feel, where the tin has a smooth feel. They feel almost like you could just scrape them away like you would with a chalky deposit, but they don't scrape away. Here are two photos, if it helps any:

      1. re: jljohn

        Hi, jljohn:

        Nice stocker, BTW.

        You know, I'm going to change my recommendation, if not my conclusion. I still think what you're seeing is AOK. But the boil in soda is going to hasten darkening, and I'm not sure you want that with your new pot. What I would recommend runs counter to the rule against abrasives, but you have a fresh lining and a lot of area that will never see contact with a skimmer. Just as a *spot test*, get some Bon Ami (not BKF) and a regular damp kitchen sponge (not Scotchbrite of any color). Pick a spot on the wall and just lightly make 4-5 little circular rubs--think "polish", not "scrub". See if the spots are still there. Stop if your sponge starts to pick up any dark gray color--that would be your tin.


        1. re: kaleokahu

          Thanks Kaleo,

          I'll pick up some Bon Ami and give it a try on a small spot high up the wall of the pot. Do your tin pots ever give off something of a metallic odor when simmering? (Keep in mind I am new to tin--I picked this stock pot and the 4 sauce pans from Rocky Mountain a month or so ago, and the shift from stainless has been interesting. I also bought the 3 qt Saucier from Falk--the one with two loop handles though--so I could really get a feel for both tin-lined and stainless-lined.)

          The stock pot was a nice find. I had to go into a TJ Maxx/Homegoods to return something, and I spotted this Mauviel 2.3mm tin-lined 13.8 Qt stocker with a lid in the clearance section. It was already less than 1/2 price, but I asked the manager about it, and she knocked some more off. So I walked out of there with it for a hair over $200. I thought that was pretty darn good for a new stock pot. I doubt I'll many more deals like that though!

          Thanks again, and I'll let you know how the Bon Ami works.