Verdigris Removal & Protection

[Wedgehead30]

I got these medals as part of a large buy. I knew they had issues when I purchased them. I just didn't know the extent. Normally I'm in the "don't mess with it" camp when it comes to antiques. But in this case the verdigris is damaging the base metal. I've been reading various sources and reviewing different cleaning methods. Some say lemon juice works great. However others say the lemon juice being an acid, will actually do more damage. Others say acetone but then there's conflicting opinions about that. Then there's jewelry cleaner, baking soda and one suggestion of Coke.

 

My goal is to remove the verdigris and stop an additional damage to the base metal and what little finish that remains. Then some how protect the base metal from future damage. I realize these are very basic medals but they are worth the effort to me.

 

I would appreciate any insight on methods that have actually worked for medal collectors. Sorry if this is a rehash but I did search and I think I've read most of the cleaning threads.

 

Thanks,

Scott

 

[LuftStalg1]

I have seen this on medals that I had in old plastic boxes with foam padding. The foam degraded and stuck to the medals leaving just what you have. As water is the most neutral and natural solvent between acid and base I would start with warm water and soap using and old tooth brush and see where that gets you. If the medals are no longer in contact with the chemical they should not continue to degrade so I think you should be safe.

 

Mark

[Darrell]

These are pretty bad and beyond repair I am afraid to say. This stuff is extremely difficult to remove, even on medals that show even small signs of the corrosion. Below are a couple of articles I found online:

 

1. If the verdigris is light, wiping with vinegar may remove it. Follow with a water rinse.

Verdigris can be cleaned from brass and copper with a solution of ammonia and salt.

These are kitchen recipes... test on some silver jewellery or an old silver dime that isnt worth much. Etching the silver is not a good thing.

Restoration and cleaning of medals @ http://www.angelfire.com/nj/ww2/ccleaning.html suggests on copper and coppers alloys: "If the area of corrosion is not great or very deep, a bone needle may be used to loosen and remove the verdigris. Badly contaminated medals should be alternately soaked in a 20% solution of sodium sesquicarbonate and worked with the bone needle".

 

2. http://www.oregonknifeclub.org/Verdigris.pdf

[Wedgehead30]

Well I tried several different methods to clean up the metal. I started with the Pacific campaign medal, as it was the worst. After numerous unsuccessful tries I went extreme. I used a small drop of Sweet's 7.62 bore solvent and a soft brush. I know, I can hear the collective gasp. But I felt I had nothing to lose. As you can see it took most of the verdigris and all of the finish off. There was also some underlying damage to the metal. Compared to the back of a NOS American campaign medal the damage is very apparent. I'm going to see if I can find a sealer that might darken it up a bit.

 

[Wedgehead30]

[capa]

Wedgehead, I am a museums guy and I did not gasp. You tried all the other options moving upward in aggressiveness then your final one worked. So I say no harm no foul and they are your medals after all. Per sealing them, I would recommend Renaissance Wax but follow directions on it. Use sparingly and wipe off excess and let it air out for a bit before enclosing in a case.

[Darrell]

Like you say you had limited options and nothing to lose. Others may disagree, but the end result was better than doing nothing. Plus, it should prevent the corrosion from completely destroying the medal.

[Old Marine]

I have had good results removing verdigris with Ren Wax that Capa mentioned. I had a holster with bad verdigris on the rivets and I used a tiny bit on a cotton swab and the Ren Wax just dissolved the verdigris on the brass and didn't stain the leather.

 

I think you did a good job on the medal.

[V42]

You did a great job in cleaning the medals. Far sight better then they were.