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May 3, 2010 12:46 PM

What's the grey residue on my new aluminum muffin pan?

I just bought an aluminum covered steel muffin pan made by Chicago Metallic. As I was greasing the tray with melted butter, I noticed my brush was turning grey. Then I tried to clean the pan with a sponge. That turned grey. I washed the pan again (as I'd done the night before) and this grey residue continued to stick to my sponge, brush, paper towel. It was at this point I abandoned my frittata preparation to pull out a non-stick version I had bought as a backup.

What is this grey residue? I've heard non-stick pans have toxins that people avoid by buying cast iron or aluminum pans. Has anybody else had this problem?

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  1. Get your money back ASAP!

    1. Did you wash it well first? It could be residue from the manufacturing process. Don't be too quick to panic, i think that Chicago metallic is a good company.

      5 Replies
      1. re: EWSflash

        Yes, I ran it through the dishwasher...

        1. re: syb

          Aluminum in the dishwasher is a no-no. The chemicals in the detergent will etch aluminum. The grey stuff you're seeing is the aluminum degrading.

          1. re: syb

            Yes, this is why this is happening. I hate to say it, but you ruined your pan. You can try scrubbing it with steel wool to see if the layer of aluminum that reacted to the dishwasher heat and hot water comes off. I was able to save a quarter sheet pan like this once, but it never got its beautiful shine back. Always handwash aluminum.

            1. re: RGC1982

              Oh no! Thanks for letting me know.

              1. re: syb

                You might be able to stave off additional oxidation by using Bar Keeper's friend or Cameo Alumninum cleanser. The pan's not toast; you've just started oxidation prematurely.

                I've had aluminum baking sheets and various pots and pans over the years and read up on cleaning them properly. I use Cameo because it's cheaper and works just as well. It's sometimes hard to find though.

        2. I would try rubbing it with damp baking soda as it is a very very mild abrasive and is water soluble. It may be some oxidation from the DW detergent.

          1. you can try cleaning it with Cameo aluminum & stainless steel cleaner. it is found with the comet & ajax. use a sponge. you will get a grey residue off even clean aluminum when using this powder, thats aluminum coming off. just scrub until it looks clean then rinse & wash with detergent. wipe dry & see if its gone. my aluminum always leaves some traces on my white towels. this can't be good for you so I got rid of everything except muffin tins & I use liners.

            1. You might want to check out your DW detergent, the newer ones very often clean with enzymes instead of chlorine bleach, which is what's so hard on what's being washed. I use an enzyme dw deterget but keep a small bottle of hard-core bleach liquid DW deterg as a reserve- sometimes things need to be bleached- then i have a choice. I find the ore modern detergents to be way more gentle on everything I put in the dishwasher.
              BTW I got my information from Consumer Reports magazine about the enzymes vs bleach.

              11 Replies
              1. re: EWSflash

                Thank you for all of this fabulous feedback! I took the pan back today and they gave me a new one (same brand, finish). They were surprised to hear about the grey residue-- they'd never seen that before.

                The label on the new pan says it is "dishwasher safe". EWSflash might be onto something with those enzymes. I checked my detergent for ingredients (Cascade with Dawn) and get this-- there are no ingredients (but it does say the bottle is made with 25% recycled plastic). In the caution notes it says it contains Chlorine Bleach as a warning not to put it on your clothes, so I guess that's the active ingredient?

                Out of curiosity, do you ever bake eggs or muffins in aluminum pans without liners? I bought the aluminum thinking it was safer than the non-stick. I'm so confused about which is "better" for us?

                1. re: syb

                  The black residue is oxidation and any metal subjected to the diswasher and more importantly, the detergent, will oxidize faster. Aluminum is one of those metals that will form a coating that will stop further oxidation, copper and silver are some others. I would try vinegar on a spot of the pan to see if it brings out some shine. If it does use it on the whole pan, rinse it off and dry it then you can spray it with oil and wipe off the excess. You may have to let the vinegar set a couple of minutes. It might be easier to just polish it again.

                  1. re: rkling819

                    DO NOT try vinegar. It will only speed the oxidation. I know this because vinegar can be used as a rinsing agent in the DW in place of jet dry. I tried the vinegar with an aluminum pan and it certainly sped up the oxidation process. Another major offender is any detergent with lemon. Aluminum + acid = bad.

                    Like others said, use bar keepers friend and a chore boy or other mildly abrasive pad to remove the oxidation.

                    1. re: dobs737

                      This simply isn't so. I have and use a few ancient aluminum pressure cookers. When they start to oxidize I simply boil either vinegar or a lemon with a pinch of cream of tartar and the black oxidized layer disappears.

                  2. re: syb

                    I think that the main thing that's affecting the aluminum pan is the caustic soda (sodium hydroxide) in the detergent. We've had this happen with quarter sheet pans. I've stopped putting them in the dishwasher, and I'll let them get a bit of oil/grease on them and let them season a la cast iron. This and handwashing leaves a patina that's protecting the surface.

                    1. re: ted

                      Great information, thanks. I will try seasoning mine pronto!

                      1. re: ted

                        ted, when you say, let them season, what do you mean exactly? I got the part about wiping them with oil but what do you do after this?

                        Resurrecting this thread because I put my Nordic Ware Commercial "Dishwasher Safe" sheet pans through the dishwasher and I got the same problem the OP has....

                        1. re: xiaobao12

                          The grey residue is aluminum oxide and its expected to rub off with uncoated aluminum pans. Seasoning the pan with whatever you try will not prevent that chemical reaction from ocuring.

                          You should never wash pans in a dishwasher, but even washing them in the sink will have a bit of the grey residue on the drying towel. The pans are not defective and are not going to dissolve or weaken over time because the amount that is coming off is minuscule.

                            1. re: Chemicalkinetics

                              I'm now resurrecting this old thread because my aluminum-clad Farberware (yes, it is 35 years old and still beautiful, or WAS), is now getting that gray on the bottom. Gray and rough, not smooth like it used to be.

                              What I don't understand is I used it for 35 years, and now use the Finish cubes, which I have done for several years. Did they recently change for forumula? I've only noticed this since I've gotten a NEW dishwasher recently. The dishwasher is the only change. Only thing different from my old one is that it now has a stainess steel tub, when my old one had the white tub.

                              If it is the detergent (and again, I've been using Finish for years with NO problems - did they recently change the forumula?)...if it is the detergent, why do they make a detergent that ruins pans, especially when many people have aluminum pans?

                              After a lifetime of not usually washing pans by hand (except my cast iron), this is going to be tough. And why does it not SAY in the instructions to not put aluminum in the dishwasher?

                              1. re: Eujeanie

                                Me too! I've had my Farberware for 32 years and it was sparkling until just within the last several weeks I noticed that the aluminum cladding on the bottom was gray - it has now begun melting away. The only thing that has changed is moving to the cascade 6x dishwasher squares with dawn.