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Aluminum vs. Dishwasher: The Rematch

So, I've done it again. I assumed that all of the pieces for my boyfriend's meat grinder were stainless steel and I threw them in the dishwasher. (We've had it for a while, but this is the first time I've used it since we moved into a house with a dishwasher.)

The tray, blade, and plate came out fine, but the bigger pieces were apparently a coated aluminum. They came out with the black residue all over them.

He read online that if you clean all of that off, let it dry, and it turns black again, throw it away. Does this mean if it DOESN'T turn black, it's safe to use? Or do I need to buy him a new grinder? :(

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  1. I wouldn't throw it away. Try soaking the pieces in white vinegar for a few days.

    1. <but the bigger pieces were apparently a coated aluminum. They came out with the black residue all over them.>

      Well, aluminum tends to discolor as it undergoes oxidation. Often it turns gray, sometime black. You may able to clean off the black residue with some acidic solutions like white vinegar or Bar Keepers Friend with some level of polishing. However, I think it will retain a shade of gray. If you want to make it shiny silver, you will definitely need to polish it by hand.

      <He read online that if you clean all of that off, let it dry, and it turns black again, throw it away.>

      Now that the aluminum pieces have been uncoated, it will be undergo oxidation. I don't think it will turn black over time, but it will turn gray. A dull silver color.

      http://periodictable.com/Samples/013....

      <it's safe to use?>

      It is actually safe to use regardless of the color.

      <Or do I need to buy him a new grinder?>

      It is up to you. It is not unsafe to use, but it will be difficult to get back to that shiny silver color and to maintain that appearance.

      1. I'm not at all worried about what it looks like. I just wasn't 100% sure that was safe now that I've put it through that.

        Thanks for the replies! I'll stick it in some vinegar when I get home and see where that gets me.

        1. Hi, Kontxesi:

          Um, I'm not sure I'd be soaking these parts in vinegar for very long... Where are the "Oh, my! Aluminum reacts with acids!" alarmists on this one?

          Keep the pieces, they're safe. If you want polish them back to shiny--I'd use 000 or 0000 steel wool. This will likely remove the residue you're talking about.

          Just so you know, aluminum "rusts" or oxidizes. But unlike what happen with iron or steel, it very quickly stops. The aluminum oxide (the "rust") actually protects the aluminum from further oxidation and corrosion. I don't think it's going to turn even dark grey unless you DW it again. No worries, just use it.

          Aloha,
          Kaleo

          2 Replies
          1. re: kaleokahu

            +1 on the steel wool. Back in the day all my mom's pots and pans were aluminum and she cleaned them with steel wool and they sparkled.
            I have a lot of original Farberware pots and pans with the aluminum bottoms (the new ones have stainless) and sometimes I just get lazy and put them in the dishwasher. the next time they need to be washed I use a Brillo pad and they're good as new.
            Finally, if you can get your hands on "kosher" soap with coconut oil, use it with the steel wool and the dulled aluminum should come back as good as new. Many supermarkets have a kosher food section and the soap can usually be found there.
            It comes in 2 colors, blue and red. Identical products.

            http://www.shoprite.com/pd/Rokeach/Ko...

            1. re: kaleokahu

              Vinegar is a pretty weak acid. The idea is to react with the aluminum, but not long enough to do significant damage. It isn't going to be eaten away in a couple of days.

            2. Cream of tartar is an excellent cleaner for aluminum that was run through the dishwasher. Make a paste of cream of tartar and water, equal parts, and use an old toothbrush or soft cloth to rub this well on the aluminum parts, then rinse with plain water and dry. If the parts of the grinder that were damaged can be immersed in water, you could also boil them for ten minutes in a solution of 2 tablespoons of cream of tartar per quart of water, then rinse and dry.

              I have tried both vinegar and cream of tartar (not at the same time!) to remove the residue from improperly washed aluminum. Vinegar did nothing but cream of tartar worked very well.

              2 Replies
              1. re: janniecooks

                That's a good idea, because cream of tartar is a stronger acid than vinegar. It should be mixed with vinegar instead of water for best results.

                1. re: GH1618

                  Hmmm. I'm pretty sure I have some in my spice cabinet....

                  I've been really busy/tired this week and have barely entered my kitchen. Hopefully I'll get this taken care of this weekend.

                  I'm reading all of your advice as it comes up and am grateful for everyone's ideas. :)