Green Copper Corrosion - Chemistry

Thanks you Kurt, you are correct. I don't know what EVO is, but if it's based on olive oil, it's a mixture of many organic acids and chemicals. These will all affect the patina of the coin. Think "like dissolves like", oils will solubilize any organic materials coating the surface, which will change the coins appearance. Additionally, the other organic acids and components are non-selective, they attack everything. My package is intended only to dissolve the copper sulfates and carbonates, while actually protecting the copper and copper oxide layer to maintain the patina.

This test is on-going, it's not over until the verdigris is gone. I'm just documenting the time progression here. I suspect this going to take a few days and some fomulation adjustments.

EDIT: Just wanted to add that my "day job" is chemist in the metalworking fluids industry. I do know a little about metals chemistry. LOL

Thad,

Have you tried potassium cyanide on Lincoln's yet? I have read a couple articles saying that is what people used in the "old" days.

"Have you tried potassium cyanide on Lincoln's yet"

Please--no more Lincoln assassinations.

Formula #8.6. Much more difficult test specimen, deep verdigris. Test started 19MAY2008 6:30PM.

Initial

While you're experimenting, it might pay to check out some of the competition: Noble Roman Coins markets Gringgott's Wizard Mixes (yes, the name was apparently inspired by Harry Potter), and the stuff is mentioned and used with high praise over on the FORVM ancients forum.

Now, your target markets are going to be different. The people who buy uncleaned ancient coins and clean them up require a completely different mindset to collectors of modern coins, because ancient copper coins are supposed to look green. But the chemicals used may be the same or similar to what you're experimenting with, or have similar effects when used on a modern "greenie".

Badthad, I agree that the coins look lighter in your "after" photos, but the background also looks lighter. I am terrible at taking photos of coins, but I am pretty good with other subjects. Maybe you can find a way to take the photos in a controlled lighting situation, ie a room with no sunlight or at the same time each day? I am also wondering if you have a "control" coin, one that has approx. the same amount of patina to compare? Your experiment intrigues me greatly and I am waiting for your success so that I can buy some!!

Those products would have nothing in common with mine. Those are dilutable solid cleaners, mine is liquid. Mine is a unique and patentable invention, even as it stands now. It's a reacted material like no other, not just a mix of chemicals.

The lighting is controlled. However, my positioning of the coin for "quick and dirty" pictures is not so good. Mostly what I do is for me and my eyes and I'm just documenting here. I don't want to spend a lot of time with the photography in these early stages. Remember, I only discovered this a few days ago, there's much to be done.