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Removing tarnish from the brass parts of an 1860's-era French clock case

I'm looking for an efficient method to remove tarnish from the brass parts of an antique French clock case (NOT the gears or mechanism). Mechanical means will be difficult since there are many small and complex parts. I tried using an electrolytic cleaning plate (parts are immersed in hot water with an alloy plate and a reactive powder), but the brass only turned darker. Any help is appreciated.

Mark Pomeroy
- Cincinnati, Ohio
2005

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See 13396.

Lee Kremer
Stellar Solutions, Inc.

McHenry, Illinois

2005

You can use 5% ammonium citrate solution.Just take 50 gm citric acid,dissolve it in 1 lit water and then add some ammonia (25%) ⇦ this on eBay or Amazon [affil links] , pH of solution must be 9.Hot solution(8oC)works faster but cold works too(immerse object in solution).Good luck!

Goran Budija
- Cerovski vrh Croatia
2005

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First of two simultaneous responses --

Lee and Goran:Many thanks for your suggestions! I'll try each one and then post the results.

Mark Pomeroy
- Cincinnati, Ohio, USA
2005

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Second of two simultaneous responses --

Don't do it! The patina on the metal gives the antique value; if you start stripping it off, it will lose commercial value. Only lightly clean antique metal with soapy water and be very careful in doing so. If you start trying to clean brass with alkali cleaners, you run the risk of dissolving the zinc ("dezincification") and this will leave you with a fragile mesh of copper and a ruined artifact.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2005