How to clean aluminum corrosion

My brothers and I are looking to clean up and possibly restore a set of German field binoculars from WWII (brought back to the states by my grandfather). They are unfortunately in poor condition, fastened in a display case for years with a copper wire which reacted with and corroded the aluminum body. The areas where paint was worn were hit the hardest. I'll start with vacuuming and brushing. Any suggestions on how to gently remove the remainder of corrosion? It seems baking soda isn't recommended for aluminum.

I don't know the quality or value, if they are high end then you may want to consider having a professional restoration done. The Germans made some superior equipment and optics. I will be watching your post so I can find our if you get a good answer because I have had some expensive camera equipment get some aluminum oxide on them and all I could do at the time was the same thing you are planning to do if you don't get better advice..

I would disassemble the entire thing and clean piece by piece... it likely has Zeiss optics (quality) and you don't want to scratch those up. A good scrub with a toothbrush will lkely get rid of almost all of the major corrosion (crystal growth), and the rest can be taken care of with a weak wash of baking soda/vinegar (quick, light scrub, immediate rinse, don't soak).

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Originally Posted by Dan Hintz

...the rest can be taken care of with a weak wash of baking soda/vinegar (quick, light scrub, immediate rinse, don't soak).

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Dan, could you give me a rough ratio for the soda/vinegar mix? I've never used the two together. Should I include any water?

Make a simple paste of water/baking soda and scrub away any residue you see with a toothbrush. You can either wash it off right then and there with clean water, or use a spray bottle filled with some vinegar and watch it bubble up (remember the volcanoes from childhood?), and then wash it off with clean water. The worst thing you'll have to fight is pitting, and that may have actually happened on your piece due to the age... again, the toothbrush is your friend. Be aware, you will likely lose some more of the black during scrubbing.

At long last, here's the "after" photo. I took Dan's advice and decided to do this myself. With the help of Google, YouTube, and a binoculars repair guide by Alii Service Notes I took this baby apart piece by piece and gave it a good cleaning and some TLC. It felt like American Restoration at my house for awhile. I was able to remove most of the corrosion using your suggestions. The main body and the oculars were heavily damaged and pitted. I gave those parts a deep hand sanding, primed, and repainted with a low-gloss Valspar implement enamel. I didn't want this to look new or fully restored so I decided to clean and leave the other parts alone; you can see the prism covers and lens decorator caps still show the original wear. The hinge and all threaded parts were seized up and the lenses were so grimy you couldn't see through them, but everything is now functional. The prisms were in surprisingly good shape. I was able to restore most of the collimation, although a professional shop could certainly fine-tune it.

We're celebrating Christmas this weekend with my family and I've got this wrapped up for my brother and father. I think they'll be happily surprised. :D

Good job! Great to see a nice restoration

That restoration came out really nice. Well done.

Can they still be used as a set of binoculars? (By that I mean that the lenses are clear and the focus is working.)

Cool, thanks for the update.

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Originally Posted by Mike Cutler

Can they still be used as a set of binoculars? (By that I mean that the lenses are clear and the focus is working.)

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Yes, they are usable as a set of binoculars. The focus works and moves freely, lenses have some scratches but are clear. I also freed up the adjustable ocular so that works now too.

will you post the recipe for mixing the vinegar+baking soda +water ? I bet that the vinegar and water was mix first then the soda added to this

I hadn't seen this thread before. You did a great job and I like that you left some of it "used" or "worn". They look great!

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Originally Posted by ray hampton

will you post the recipe for mixing the vinegar+baking soda +water ? I bet that the vinegar and water was mix first then the soda added to this

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Ray, I followed Dan's advice and added enough drops of water to baking soda in a dish to make a paste when mixed; the consistency was a little thinner than toothpaste. I scrubbed the paste on with a toothbrush. I didn't measure but I tried a half water - half vinegar mix in a spray bottle and used that to rinse/wipe off. That didn't seem to be very effective so I then tried straight vinegar.

By the way, there were tears flowing at our family Christmas after my brother opened these. Success!