Removing Verdigris

[LINCOLNMAN]

I'm considering buying a scarce, but inexpensive ($100) 18th century medal. There are a couple of verdigris spots on the reverse. I would pass but may have to wait years for another to pop up. Any way to safely remove verdigris without really messing up the surface? I'm never going to have it slabbed so don't want to have it professionally conserved, just DIY for this. I'm only concerned about the look, not whether it would ultimately straight grade for a future owner. 

[Just Bob]

It can be removed by a long (maybe 6 months or more) soak in olive oil. The problem, though, is that verdigris which has been on the coin too long will leave a pitted or corroded looking area when removed.

 

I went back and found a response to an old post of mine by Conder101 from 10 years ago, concerning a token that had the same problem:

 

"Looks like active corrosion. Might try a soak in an oil based product such as olive oil, mineral oil or blue ribbon, then use a rose thorn to remove any loosened corrosion product. You may have to do a few cycles of soak then thorn. (The thorn is also good for getting any dirt or "crud" out from around the devices, it is soft enough it should not scratch, strong enough to dig out the crud, and comes to a small enough point that it gets into the smallest places.)

 

Then use acetone to remove all of the oil and to throughly dry the token. (one thing the corrosion need to work is to water and the rough area of the corrosion will hold onto water molecules very well. The acetone gets in there and "dissolves" out the water and carries it off. It acts as a drying agent.) After the acetone you might want to then apply a very thin layer of blue ribbon or mineral oil to the token to seal out moisture from the corrosion area. (The oil fills the nooks and crannies in the corrosion keeping the water vapor in the air out of them.)

 

Now the corroded areas will still look rough and pitted but it should look better than the active corrosion and will help stop it from getting any worse." 

  

[LINCOLNMAN]

Many thanks Bob. 

[Just Bob]

On 9/12/2018 at 3:04 PM, LINCOLNMAN said:

I'm considering buying a scarce, but inexpensive ($100) 18th century medal. There are a couple of verdigris spots on the reverse. I would pass but may have to wait years for another to pop up. Any way to safely remove verdigris without really messing up the surface? I'm never going to have it slabbed so don't want to have it professionally conserved, just DIY for this. I'm only concerned about the look, not whether it would ultimately straight grade for a future owner. 

On a personal note, I don't have a problem buying a token or medal with issues, if I know that it may be the only chance that I have to obtain one - provided the price is right. A lot of the tokens that I collect have been dug by metal detectors or found in old buildings, so most of the known examples have problems of one sort or another.  If I ever do find a better one to replace it, I can always sell the first one. In addition, I have even intentionally bought coins or tokens with problems in order to have something that I can handle, examine,  and even carry around without any risk of damaging it by dropping or otherwise mishandling it

[Conder101]

One thing you have to be careful of with medals is sometimes they have an applied patina from the mint and there may be a chance that attempts to clean or remove corrosion may remove that patina as well.

[LINCOLNMAN]

Here's the medal that prompted this question. I may not see another for a while. Find most of them in European sites. I think I'll pick it up, thanks. 

[coinman1794]

The verdigris seems minor enough that the options above just might work with minimal consequences.

[KarenHolcomb]

Hey Bob! Great info there on the thorn use. Never would have thought of that in a million years. My wood skewer doesn't damage but also doesn't get inside the letters like a thorn sure would. Nice call Dude. Also an FYI here...I do NOT recommend getting that Verdi-Care garbage shops are selling now. It does not work and is very expensive.

[Just Bob]

6 hours ago, KarenHolcomb said:

Hey Bob! Great info there on the thorn use. Never would have thought of that in a million years. My wood skewer doesn't damage but also doesn't get inside the letters like a thorn sure would. Nice call Dude. Also an FYI here...I do NOT recommend getting that Verdi-Care garbage shops are selling now. It does not work and is very expensive.

I can't take credit for that idea. I learned that from two seasoned collectors, Conder101 , who I quoted above, and another poster who went by "michael." (if you go back and read older posts, his avatar was Pikachu. He didn't use punctuation or capitalization, but he was very knowledgeable. When I came back to these boards, I noticed that he was no longer here. I have often wondered what happened to him.)

[KarenHolcomb]

12 hours ago, Just Bob said:

I can't take credit for that idea. I learned that from two seasoned collectors, Conder101 , who I quoted above, and another poster who went by "michael." (if you go back and read older posts, his avatar was Pikachu. He didn't use punctuation or capitalization, but he was very knowledgeable. When I came back to these boards, I noticed that he was no longer here. I have often wondered what happened to him.)

Way to spread the credit. I do remember seeing the little yellow spooner. I too had a friend here that disappeared and I miss dearly. 

[Keigwin]

I've had great success treating verdigris on small and large cents with Verdicare (formerly Verdigone). Google it and you'll find posts with before-and-after images.

Lance.

[KarenHolcomb]

Really? I bought my tiny bottle from Wizard's and I didn't get any satisfaction at all. 

[dleonard-3]

Another technique is to use a stencil brush.  No Chemicals, no abrasion.  You carefully hold the coin by the edges, gently apply the brush bristle tips to the face of the coin without moving, then give it a little pressure to anchor the bristle tips in place, then carefully and slowly move the handle in a circular motion being careful not to allow the bristle tips to move.  What this does is gently allow the bristle tips to penetrate the "goop" and loosen it from the coin's surface.  Done right, it will not leave any scratches, won't alter the surface "skin" or color, but will remove foreign soft substances.