Hey all, Just picked up a few “problem” coins from a local seller. I’m excited to see what I can do with them in my ever-evolving adventure/education with VerdiCare. Here are the before pictures. I am starting with a 90 minute application of VerdiCare to the entire Obverse. Will post pics throughout the process. I like experimenting with coins like this because there is only upside. I can’t really mess them up much more.
No progress after 3 hours of VerdiCare. I’m going to let it sit overnight and see what’s what in the morning.
Generally you have to wipe it off and the verdigris comes off with the wiping. It doesn't disappear, but becomes loose enough to be wiped off and what remains is passivated.
I treat the entire surface overnight, then rinse with water. Flip it over and treat the other side the same way, if needed. I also use a gentle Q-Tip or wooden toothpick occasionally. Haven't had one quite as bad as yours however.
It's always good to experiment so you can see things with your own eyes. But sometimes it's been for you kinda like it was here - https://supplies.coinweek.com/images/Verdi-Care-Typical-Results.pdf But with coins like the ones you pictured Mark, those were a lost cause before ya ever started. You knew that though for as you said you certainly couldn't hurt them, they had only upside. So, I'd agree, no harm in trying. That said, Thad (the inventor and maker of Verdi-Care) has posted for years on the subject. And even the instructions that come with the product clearly state that it will only work on light to moderate verdigris. The thing that people have to understand is what "light to moderate" means, how it is defined. In simple terms it means a fleck or two or verdigris (light), or a few to several flecks (moderate) of verdigris scattered about the coin. That's it. Much more than that and well, the odds of success are almost non-existent. And - the instructions also state that there is always going to be irreparable damage underneath the verdigris once it is/has been removed. Users of Verdi-Care also have to understand what verdigris is. Verdigris is the green stuff, that's it, that's the only thing the Verdi-Care will take off, the green stuff. And that green stuff is nothing more than what used to be molecules of copper, but it got changed into the green stuff when that copper corroded. And once you take it off the damage and or pitting from the corrosion is still there - every single time. And the green stuff itself, it's not causing corrosion, it's merely the result of corrosion. The corrosion is caused by moisture and oxygen reacting with the copper, just like moisture and oxygen causes rust on steel or iron. Rust, and the green stuff - they are both the result of corrosion - not the cause of it. The point here is taking the green stuff off the coin will not stop further corrosion from happening, and by the same token leaving the green stuff on the coin will not cause more corrosion either. The only thing taking it off will do is, in the eyes of some, make the coin "look" better. At least hopefully so.
Here are some examples of using lye to remove green encrustations, including verdigris and other types of corrosion. On this billon/silver coin, lye removed about 90-95% of all surface encrustations. Downside is a softening of details - especially in the reverse legend. On this bronze coin, in addition to verdigris there was also other types of mineral encrustation. Treatment with lye removed up to 90% of the encrustations, and did not lead to as much of a loss of detail as the silver coin exhibited.
If the substance is indeed verdigris, then acetone will generally not make much of a difference, in my experience