Let's remove some verdigris, shall we?

Doug's so old there was nothing in existence to be secret about.

 

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Oh shucks, the secret is out. Authentication Tip #1 from a seminar in the 1970's: Note that the stopper is split. This allows a collector to position a coin at an angle in order to look for the "seam" commonly found on coins with added mint marks.

 

Ive only used natural goats milk soap and water. But I'm honestly intrigued with this verdigris removal process. I have a minor in chemistry I think I know how the verdigris remover works. I want to see the finished coin!

I have quite a few copper coins with this issue.

 

This doesn't explain the contents of the verdigris remover. Did I miss something?

 

Let's see if I'm correct, verdigris is oxidized copper and carbon . So the formula would look something like Cu2CO2, sorry don't know how to do subscript without Microsoft Word .

You somehow want to just remove the verdigris without harming the coin. So you want to break the bond between the Cu and the O2, so both dissolve. I don't think you need much more than a few household chemicals. Some Sodium Hydroxide? Perhaps Eletro chemistry is involved. IDK....!

Im done trying to remember all that stuff from 20 years ago. Ok I'm ready for the big reveal.

 

Not a chemist here but sodium hydroxide might be a bit harsh to use on copper.

 

Well, first of all, the VerdiCare formula is proprietary, highly effective, and apparently a good seller, so I can't imagine @BadThad would be eager to reveal the secret!

Second, VerdiCare is a lot safer (for both coins and people) than a strong base or acid.

Third, I'm not a "real" chemist either, but I've been following discussions here about this for several years. I think the key things are a complexing agent to solubilize and lift away the verdigris, and a protective agent to keep it from re-forming once it's gone. I suspect that there's a silicone compound involved for the latter part. I'd expect some sort of ammonium compound for the first part.

Again, though, I'm happy to spend money for a product where someone else has done all the development and testing.

 

Yeah, wouldn't take the chance either on a coin like that. Let the guys who do this for a living make the stuff.

Lye is a bit harsh, but I might try an experiment, if I get the chance later today. I'll let you know how it goes.

 

btw... my plan is to use a curved bottom shot glass to do the soaking. Gets both the top and bottom of my verdigris'd cent.

 

Remember to use a glass you don't care about. Strong bases like lye will etch glass as well, eventually.

 

I'm anxious to see the results. Just don't be breathing the acetone, since that's when it is dangerous .. use a vent or hood or small fan.

 

That's been my glass of choice all along, until I got rid of them all when I downsized to move. The current glass is because Walmart is walking distance for me.

 

Hmmm...can't load a GIF

 

Here's my setup so far:


The last one is an ultrasonic bath filled partly with tap water. In the shot glass is about half a teaspoon of sodium hydroxide or lye. Results will be posted even if they are disastrous.

 

Whoa.

 

Well I think we can all agree that the coin was junk to begin with. But the verdigris has disappeared without toning the coin or corrosion of the outer layer of copper.

Here is the result:

 

I will try an all copper coin with verdigris, and we'll see if it can just remove a few spots. I'll have to find one. But I keep all my copper so it won't take too long. Am working under a powerful bathroom fan and wearing safety glasses....Also listening to classical music. I'll keep doing this until Beethoven's 7 Symphony is over and then I'm just gonna relax.

 

Ok..... here is the best example I could find with some verdigris. All the others are just way too environmentally damaged.

I know some of this is toning, and quite a bit of carbon build up, but this isn't a 1793 Large Cent. Ok will post the results when done.