Aluminum meat grinder parts were washed in the dishwasher. What now?

November 4, 2010

A friend borrowed our Meat grinder and washed the aluminum parts that are not dishwasher safe in the dishwasher! The once pretty shiny silver looking parts are now dark gray and leave a black tarnish on your fingers. How can I clean it, to get it to the point where it will be safe to use again?

Tawny Dunlevy
Homemaker - Sitka, Alaska, USA

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November 4, 2010

Hi, Tawny

Personally I think it's safe to use, and I believe if you look it up in authoritative places you will find the same opinion expressed by the Alzheimer's Association, EPA, etc. But that black smut is unappealing and if you can get rid of it even temporarily, consider yourself lucky.

I used your inquiry as a teachable moment for myself, taking an old aluminum ice cream scooper that has been in the dishwasher a hundred times and seeing what I could do with it. Rubbing it with a cloth soaked in vinegar took off loads of the black smut, but was probably generating it almost as fast as it took it off. After I rinsed it, not much further black smut came off, and it was darker in color because I had dissolved any white corrosion products. I then tried a sulfamic acid metal polish and the experiment went pretty much the same. Not having any Mother's Mag & Aluminum Polish at hand, I tried rubbing compound, and the result was slightly better.

Moving on to conjecture, I think you could brighten it up a little bit and lessen the black smut temporarily if you were to buff it with a power tool (a buffer, or at least a buffing pad on a high speed drill) and the Mother's. But I think once the anodized coating is gone, it's gone, and it will not be really shiny again. Sorry.

Regards,

Ted Mooney, P.E. RET finishing.com Brick, New Jersey

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November 5, 2010

You will probably give up and buy replacement parts.

James Watts
- Navarre, Florida

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November 9, 2010 It has been a while since I've read through it, and I don't have my copy handy, but I recall Wernick Pinner and Sheasby => stating that you could get really good corrosion resistance by submerging aluminum in boiling water for 24 hours but that it wasn't economical for most manufacturing purposes. In this case however, if you CAN brighten it back up (even temporarily), if you have a way to boil it for long enough it MIGHT stay that way. Mind you, I've never personally tried it. Good Luck! Jim Gorsich Accurate Anodizing Inc. Compton, California, USA

Surface Treatment & Finishing of Aluminium and Its Alloys

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December 8, 2010

I washed my aluminum pressure cooker in the dishwasher. The manual says not dishwasher safe on it; however, I did not see that until later. Instead of being shiny silver it is now dull and has a pink/purple/green tinge to it. Is this safe to use again or should I discard it?

Cat Welz
- Vernon, Connecticut, USA

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December 9, 2010

Hi, Cat.

I'd guess that the tinge is a diffraction pattern caused by the last of the anodized coating (sometimes you see automobile headlights changing color as they approach you if they have anodized reflectors). With a ruined pot, you sound like the perfect person to try Jim's theoretical cure of boiling for 24 hours. Please let us know what happens.

Regards,

Ted Mooney, P.E. RET finishing.com Brick, New Jersey