Another verdigris discussion!

I've been searching the forum for a good coin repair/Verdigris removal method and found some GREAT material from user Fluke (seems he is no longer around?)

Namely this thread involving an amazing flame technique:
https://en.numista.com/forum/topic41034.html

But then we other methods such as hot olive oil:
https://en.numista.com/forum/topic52932.html

Searching the internet there are more generic chemical methods as well: Electrolysis cleaning, Acetone rinse, toothpaste scrubbing, and so on.

I would like to try one or some of these methods on inexpensive coins. But the problem is how to determine which method to use? Depending on the coin type, metal, degree of corrosion... Should coins of Bronze, Copper-Nickel alloy be treated the same as Copper ones?

Assuming verdigris is what I'm actually dealing with

Hello,
I tried few different ways to clean verdigris too:)
Thanks to Fluke,I agreed...if on copper...fire is the king:)
For the rest alloys,my general results are:
option 1,baby-verdigris which just started-just a bath with some Calgon between fingers is fine,and doesn't change noticeably coin's colouring.
option 2-heavy verdigris that either you clean,either get the coin lost forever-frying it just as french fries in oil at high temperature,and cleaning again with Calgon after that...you may have holes in the metal where verdigris was...but if it got that advanced...I still prefer holes rather than verdigris:)

Yes verdigris it is. Sadly Fluke does seem to have moved on but his methods required a pretty high degree of expertise and from many conversations with him on the subject it seems it can be quite dangerous.

There isn't really a 100% effective method to deal with the green rot and for common coins it's probably not worth the effort. Any kind of oil will help to stabilize the coin and prevent further damage but there's no way to restore the coin's surface. On older coins a degree of pitting is usually acceptable so the best advice is to practice on low value modern coins and apply what you have learned to the older, more valuable ones.

The worst thing you can do is to leave it alone. If it's active it's slowly eating away your coin and if left to run it's course you will end up with a small pile of rusty dust. There are exceptions to this rule though, where you will find ancient coins with an even green patina. It's far beyond my pay grade to explain the mechanics of it but they seem to be quite stable and actually the green patina looks quite nice. I leave these alone.

You can buy several inexpensive brands of treatments for verdigris which work quite well. A quick internet search will point you in the right direction.

From what I remember, Fluke had health issues which means he had to step back for a while. Hopefully he'll come back at some stage, although if he does I think he'll be disappointed with the way the forum discussion has declined.

Hey everyone,

I did eventually find some helpful bits and pieces online (Sometimes the problem is too MUCH information available, when not everyone agrees)
In response to i_getsov, I have never heard of Calgon. Perhaps in is not a common brand in the USA.

I ended up getting the best results with a distilled water and baking soda soak for 1-2 hours, followed by a vigorous scrubbing between fingertips, underwater, in a soupy baking soda mix. Yes, scrubbing - I really had to work the baking soda into the details to get all of the green corrosion out. Then I gave it a nice rinse with a spray nozzle from the sink and a short soak in acetone.
Here is the result:



You can see the "before" reverse in my photo above. I assume the dark areas are part of the surface and unaffected by the baking soda.

Quote: "neilithicman"​From what I remember, Fluke had health issues which means he had to step back for a while. Hopefully he'll come back at some stage, although if he does I think he'll be disappointed with the way the forum discussion has declined.

​That's what I was afraid of. I hope he is doing well.

Had a quick chat with him I think it was last week, he was in hospital but is out now and seems he is doing well again.
He is busy at the moment of course with the festive season and having a fiancee now.
But not sure if he will be active much on Numista anymore.

I have also had a few enjoyable communication exchanges with Fluke, including a remarkable restoration he did for me, and am pleased to hear that his health has stabilised again. I wish him and his fiancee the best of everything for the future.

Oh and by the way. this may not be what you want to hear but the dark areas that remain after the treatment above, well they just may be the root of the corrosion and if not removed or stabilised, it is possible that the green may return in time.

Finally some good news!!

Quote: "radrick007"this may not be what you want to hear but the dark areas that remain after the treatment above, well they just may be the root of the corrosion and if not removed or stabilised, it is possible that the green may return in time.

​I was curious about it returning - I'll keep an eye out it. Thanks!

Quote: "frowell"​

Quote: "radrick007"this may not be what you want to hear but the dark areas that remain after the treatment above, well they just may be the root of the corrosion and if not removed or stabilised, it is possible that the green may return in time.

​​I was curious about it returning - I'll keep an eye out it. Thanks!

​Verdigris needs oxygen (and to a lesser degree, moisture) to propagate so if you can keep these two elements away then you should be on to a winner.

Quote: "radrick007"​=1em​​Verdigris needs oxygen (and to a lesser degree, moisture) to propagate so if you can keep these two elements away then you should be on to a winner.

​What is your opinion on applying lacquer? It certainly changes the appearence of the coin but prevents harmfull elements from reaching the surface. Especially for copper coins.

I have seen copper and bronze coins lacquered before but I am not a fan of the look myself, I would prefer to keep them in holders/airtites.