Cleaning Copper

Any HCl solution will dissolve copper oxides and other verdegris without touching the metal (being a noble metal). Muriatic acid cut 1:3 will do it just fine. Mind to rinse it very well (first with a mild baking soda solution) and wear protection because HCl is a strong mineral acid.

Instead of vinegar + lemon juice, you should try vinegar concentrated with salt. Leave it in for a few days to a week (make sure to fully submerge it!) and it's good as new.

Beware of bimetallic things like pots and pans with copper bottoms, the stainless will corrode away with HCl and probably cause electrolytic corrosion in the sour salt solution.

Tim

Along with Tim's excellent advice, one can clean copper with dilute sulfuric acid as well. It, too, dissolves oxides of copper, but not the copper itself. Great care must be used so you don't destroy things with the acid. It's not as forgiving as HCL. Only copper can be inserted, not brass, or anything ferrous.

Harold

The advice you've gotten is good, but let me add one bit of caution about hydrochloric acid (muriatic acid).

If you store it indoors, even in a sealed plastic jug it will cause severe rusting of all steel and iron in the vicinity.

I set my jugs of muriatic acid into a plastic bucket kept outdoors. To keep out the rain and dirt, I cover all that with a larger bucket, turned upside down.

Besides the storage issues, there are a whole bunch of safety precautions you must use when handling any strong acid. If you're not familiar with them, ask for help from someone that is.

Best regards,

Orrin

Yep!

Harold

At the risk of stating either the obvious or the inappropriate: there are a number of copper-cleaning compounds sold for kitchen pots and pans. No safety issues, rinse off easily. Cost more than mixing your own but are quick, risk-free and easy.

Don't know about you but I often find myself reinventing wheels, then kicking myself for the lost time.

I can't help but agree, but the acid process can be more aggressive for those cases where the chore at hand is extreme. For instance, you can clean beryllium copper after heat treat and have it look great. That's assuming you don't have a controlled atmosphere furnace at your disposal, and I don't. After silver soldering, too.

Harold

Harold

How about Brasso - used by every service person for years on their brass. Sold where good food is.

Martin

Household products (Wal-Mart, aka ASDA in the UK): Twinkle Brasso

Auto Store or possibly B&Q: Flitz Mother's metal polish Simichrome

Chuckle!

Brasso? I spent 6 years of my life with Brasso, polising my brass while in the Utah National Guard. Acid works much easier!

Harold

Thanks for all your suggestions.

I have found that Brasso is fine for some of the small pieces and works really well, but some of the copper I have are in the form of sculptures and are left outside and the normal green patination occurs.... brasso is fine to remove this on a small piece but on a larger one I would be there till kingdom come. I reckon that I will have to go for the drastic route and get some acid solution with the appropriate protective gear.

Thanks for all your help.

Craig

I have to ask why you are removing the patina on an outdoor sculpture? Most people like it and want it. Keeping it shiny over the years will be a lot of work.

Lane

I understand Harold - two with one blow - finger prints and brass work. :-) If brass is really bad, green pad, then acid clean, then Brasso polish.

There is another polish - sold in Autopart stores - Al polish - I highly suspect it is diatamatious(sp) earth in a wax. Great polish for most every thing...

Martin

Trying to take the magic color off ? hum.

Martin