BKB

the last one is not 1771 GX, I know what you are talking about -- 1771 "valak". I still think that one was a pattern. Its design was picked as the design of choice for later years, because it did not contain any attributes of the Russian authority (Cypher, etc.) I found that 1772 "valak" is harder to find -- I still do not have one. I got my 1771 "valak" from Basok some years ago in a dreadful condition. Never was able to improve it yet.

I am no big expert, but my understanding is that all 1771 are considered patterns. However, some of them were issued in such number that makes them easy to find. Some of them are just impossible to find. Some are possible, but very expensive like 5 kop or the "cross" As to easy varieties -- I was able to buy one for like 175 in bad condition some years ago.

I wish I was at that 18th century sale with enough $ to buy everything...

cheap

cheap, unless there is tooling or traces of cleaning...

some sort of copper/nickel. These were sold in huge amounts. I should have a set or two laying around somewhere. I never saw these in precious metal.

Do not know what you mean by "perfect", but aside from the rotten coin that came up 3 times (Gorny, Markov, Molotok), the other coins do not exhibit much (or, any) wear. Here, the wear is also somewhat uneven. I am not saying this indicates that the coin is not genuine, just something to look into.

where would all that wear come from?... I do not think I have ever seen a presentation specimen with so much wear.

this can be done on a lathe, or a precision grinder used to sharpen mill bits...

there is an influx of fake 1796 and other Paul's recoinage on the market. There are guys in Russia that claim to know the difference in dies. I am not in the know, but I just stopped buying overstrikes altogether...

that was somewhat reasonable. Looks like the coin is better than the grade...

I apologize if my questions sounded abrupt. Did not mean for that. I was surprised to hear about white corrosion -- never saw it on copper. On silver and billon, yes. I guess that is what the vinegar is used... I tried it on copper with no success. Thank you for your response.

Was that a copper coin? What white crust?! This affliction I have not seen yet...

Maybe ear wax? P.S. Nice story, but, what relation it has to the present discussion I am yet to understand. Please enlighten.

Somehow, with the 2 kop, I was able to retain the original patina. With an overstrike -- there is no patina -- just ugly black and green stuff. I live easier with caverns, because I know that the green stuff will eventually eat the coin alive. The only raeson I bought the overstrike was because it was cheap (about $200). Not too many interesting coins you can buy now under $1000. In the condition it is in, I do not really care about the size of the mintmark, - cannot put it in my collection anyway...

The idea is not to remove a BIT of verdigris, but to remove all of it, if that what you call it. Looked at that link -- it may be a good conservation technique (cannot tell from the photos), and a dirt cleaner. But, where did you see that green stuff on those coins? I want to see him try it on what I had to work with... I am sticking to my method. I do not know what is in that chemical concoction of his and how it will react with an 18 century copper alloy. There is this stuff called MS70. Tried it on a bronze soviet coin ones -- turned the coin green and blue on contact. I do not know what he has against oil, and how he says that oil is agressive. I just bought a 1791 5 kop Paul overstrike that is rather black. Had it in oil for a month. Did not change color one bit. Still black and ugly. All I wanted is to get rid of light green corrosion, and to lighten the color a few shades, so I do not have to tilt the coin to see the eagle. As you can see, the oil also did nothing to the green stuff - would have to remove it manually. The only logical next step I see is boiling it. However, from the way the surface looks, I can tell that it will do nothing except getting rid of the green stuff. However, I know of no other way to revive this coin... As to mailing the stuff to Australia. Get someone here to purchase it, if it is commercially available, and then mail it to you...

Read that article on bronze decease -- wow. Too involved for me. Let me recount all methods that I tried so far. That would be a good "Emanuel" on what not to do, and what can be done if you are brave :-) I am recounting 8 years of experimentation. I would not try it on expensive coins first. 1. Lemon Juice + salt. This was the first method I tried. Basically soak your coin in lemon juice with salt, and it will clean it. I want to kill the moron that advised me to do it. Result -- destroyed coin. No, it cleans everything, including the metals mixed into the copper. Leaves pitted copper surface. Lemon juice without salt did not destroy the coin, but also did not clean it. 2. Next came vinegar. Did not do anything. Do not know what that guy cleaned with it, but the green remained. 3. Then came soaking in soap + water solution. great for dirt, but really feeds the corrosion. After that experiment I tried to keep it away from water for a while. 4. Then came soaking it in olive oil. Even after months, I found it not very effective. First, after the olive oil softens the green crust, you need to manually clean it off. The process needs to be repeated. It is hard to get the green stuff out of the pores and cavities. I hate any mechanical cleaning, so I stayed away from it. 5. Next came the electrolysis. I read about it on some antique coin forum. Tried it. Would not do it again. Only ones I succeeded to clean a coin, which was covered in black crust with some iron oxide inclusions. During electrolysis process in saline solution, the stuff just popped off. Involves water, so it is not a good idea to submerge coin afflicted by that green corrosion... 6. Next I tried boiling in olive oil. Not bad, if you can stand the smoke and can get the oil hot enough. 7. Next I tried boiling the coin in water with baking soda. The best way to get rid of the green stuff! Kills all patina. Coin becomes pink like baby's ass. I guess, the patina will return in 100 years... 8. This coin was cleaned like so: a. soaked it in olive oil for 2 weeks, then b. boiled it in water with baking soda. Miraculously, the patina remained, and the green stuff is gone. Maybe the olive oil not only softened the crust, but also protected the patina somehow? I do not know.

I am going to write that when I come back home. Did not know whether there was any interest...

Now, normally someone would see this topic, and would start screaming that coins should not be cleaned or even touched in that way... However,sometimes you get a copper coin, and it has that green crust or reddish dust on it. Do you know, that this stuff can just eat the coin alive, and can even infect other coppers in your collection? Believe you or not, that green corrosion is contagious... Now, what do you do? The best way, of course, is not to buy coins with that stuff on. However, I have seen a lot of coins on this forum that sport that green stuff. If you buy on ebay, Photoshop can do wonderful things to photos. Or, sometimes, I can't let a rare or scarce coin slip away... Then you get it, and start scratching your head(or, at least, I do.) What to do if you already bought one with that green stuff on? Is there any interest in a thread like this? Would anyone like to share their experience in getting rid of green or reddish corrosion found on Russian coppers? Maybe, a way to get rid of that godawful sulfur stuff used by some to create fake patina on Russian silver coins? Or, how to get rid of iron rust on copper or silver coins (from that metal can they were hidden in for 100 years...) My example: Before: The true color of the green was a bit darker. After: It does not always come out this nice (the coin is a few shades darker than the photo and there is some red under the brown), but it usually largely depends on how deep the corrosion is. This time it is was reasonably surface, with only a small area affected. There is some pitting, but it is better than before. At least I think so, and, the main thing is, -- the coin is hopefully safe now. There are a few spots left, but if they do not grow, I will leave them alone. Anyone care to share the result of their experiments?

Not as nice as they could have been... I wish they were all like 1801 but without those ugly scratches

I think this is all I have in terms of 5 and 10 now:

The polushka is missing from these photos no longer:

I still like it

Yep. looks like it is the same coin. Mule error.