Before I go at it with a too aggressive caustic approach, what is the best approach towards cleaning this medal (small area at about 7:00). Obviously I don't want to damage it nor do I want it to look so clean that it sticks out.  

Thanks!
Kim

 

What is it? Is it oxidization or just some gunk that got stuck on it?

Hunt


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Looks like green verdigris to me - not a hunk of 80 year old pea soup!

https://www.rubylane.com/blog/categories/jewelry/verdigris-green-gunk-how-to-clean-it-from-your-jewelry/#:~:text=Soak the piece in straight,not be soaked in vinegar.

 

https://nogemunturned.wordpress.com/2015/11/04/safely-remove-verdigris-from-vintage-costume-jewelry/

 

Here are some articles to look into. Looks like you should be pretty careful with these. I would recommend not going to far on it, Verdigris can threaten the integrity of the metal, as well as affect the metal plating. Basically if you take it all off you may find that you have a little divot where the verdigris is. Maybe a soft toothbrush with a vinegar and salt solution on the bristles with light circular moth scrubbing should help to clean some stuff off. I am about 99% sure there may be a noticeable difference in terms of the patina on the newly cleaned area opposed to everywhere else. A little bit of light scrubbing may end up yielding good enough results, while only removing some of the verdigris and leaving most of the patina in tact.

 

Let me know how it goes!
Hunt

Thanks Hunt! I think I got it!

Here's a before and after:

 

I started with a soft toothbrush, graduated to a cotton cloth and toothpick, introduced some mild dish soap and water, rubbing & wiping. Then (please don't hate me), I used fine steel wool very selectively on the rays - teenie little pieces of it. I think it turned out good!

Looks great! I was worried that it would mess up the patina, but it seems like it turned out nicely! Nice job, glad it worked!

Hunt


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Thanks ... I appreciated your suggestions.

Yes, looks good. I wouldn't use vinegar or any other acid because it can really mess up the color. I would have said try a toothpick, but you already cleaned it up well.

Since you cleaned off oxidation and debris, you really, really need to seal it. Museums use Renaissance Micro- Crystaline wax. I use it on a lot of my ordnance, large pieces to small, and many of my rarer cartridges. 

I think if it stays dry and isn't subject to temperature chances, it should be good. The verdigris probably came from moisture. Brass isn't as susceptible to deterioration as iron. But I guess sealing it wouldn't hurt either.

14 hours ago, Reforger said:

I think if it stays dry and isn't subject to temperature chances, it should be good. The verdigris probably came from moisture. Brass isn't as susceptible to deterioration as iron. But I guess sealing it wouldn't hurt either.

Sealing it with Renaissance insures it remains in good condition for future owners and generations. Plus your ownership becomes carefree not having to check on it. Who knows when it is tossed into a box in some humid storage unit, the next owner will be glad you did it...which is exactly why many museums use the wax.

You‘re right, didn‘t think about that aspect.

good suggestion.  I think I'll do that.

I've had a lot of luck with toothpaste for removing verdigris

I‘ve had the problem that toothpaste cleans metal very well but it doesn‘t take long and it tarnishes again and leaves stains/discoloration on the surface. Doesn‘t look great when it has dark stains and fingerprints visible on it.

I've cleaned 120+ year old with toothpaste 5+ years ago, no return of verdigris. No fingerprints, either.

Renaissance Micro wax is the way to go to preserve the item. Cleaning you can try  pure acetone, as I use it to degrease very dirty coins etc. If you use it it I would definitely try it on something similar first. I also use a commercial grade ultrasonic machine with only distilled water in it. do not use it on enameled surfaces such as badges because it can take the enameling off. In the coin conservation industrry, TOOTH PASTE is a definite no no. It is an abrasive.