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FORVM`s Classical Numismatics Discussion Board  |  Numismatic and History Discussions  |  Uncleaned Ancient Coin Discussion (Moderator: bruce61813)  |  Topic: How do I clean this wonderful Ptolemy coin without damaging it? 0 Members and 1 Guest are viewing this topic. « previous next »
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Author Topic: How do I clean this wonderful Ptolemy coin without damaging it?  (Read 4042 times)
oneill6217
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« on: October 19, 2011, 11:55:55 am »

Is there a way to get rid of this green build up without damaging the coin?  I really want to see this coin without it.  It would then be my prize piece (I am a newbie).  HELP!  Smiley

30mm

This is a Ptolemy coin right?
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oneill6217
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« Reply #1 on: October 21, 2011, 11:38:19 am »

Waaaaaaaaaaaaaah.  I damaged it.  just a tiny nick on the side, but it was perfect until I broke off a piece of that green monster.  I feel like an idiot.  Should have just let it soak forever.  I am soaking it now to try and get the rest of it off.  I will post it when I finish.  It should still be an awesome coin, but I really wish I had not broken that tiny piece off of the side.  Underneath the break (about 1.5mm, linear along the outside edge) it exposed white metal underneath.  Were these coins filled?

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casata137ec
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« Reply #2 on: October 21, 2011, 05:54:42 pm »

Broken how? A chunk broke off of the flan or simply a break in the patina? As for the white metal...renegade is working on a similar coin and in the bare metal areas it looks like white metal too. I wonder if it is a reaction to whatever soil it was buried in? Could it be caused by certain metals leaching quicker than others? Maybe crystalization? I dunno...but I guess if the coin was brittle enough to pop off a piece it could be any of the above!

Chris

PS How are you attempting to clean? What tools, soaks, etc.
C.
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Salus Populi Suprema Lex Esto - Missouri 1822

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oneill6217
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« Reply #3 on: October 22, 2011, 01:06:57 am »

Well, it is just a break in the patina, but still a bummer.  I was soaking it in olive oil for about two weeks.  Then I got impatient and used pliers to break of the part that sticks out beyond the coin.  I misjudged that.  Stupid move.  Oh well.  It is soaking now.  I hope it works eventually.  Thank you!
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casata137ec
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« Reply #4 on: October 22, 2011, 08:10:38 am »

Pliers?  Shocked Not generally a tool used for cleaning ancient coins...

There are probably a couple of ways to clean this but I am only gonna focus on one. Manual reduction.

Pull your coin out of the olive oil, fill a bowl with water and dishwashing liquid ("dawn" works well), get a toothbrush/nylon bristled brush and scrub the heck out of it. When no more olive is evident, stop scrubbing. Dump the sopay water, refill with clean water, scrub the coin. Dump. Throw away the olive oil.

Now that that is done, don't waste any more money on olive oil, but invest in a gallon or two of distilled water (better, cheaper and easier to clean up when spilled) from your local grocer. Usually found in the laundry aisle.

Next, you are gonna need some tools...not found in your standard toolbox. The most important one for this particular coin would be some sort of dddp (diamond dusted dental pick). Manual reduction is exactly what it sounds like, slow reduction of the encrustation. Starting on a likely spot, and using light circular motion, get to work. Use tons of patience and only get close to the flan, not all the way to the flan, as this type of crust somtimes eats into the coin and if you remove it all you will have a nice divot where the surface should be. On a coin like this, I limit myself to about 10-15 minutes of reduction per session, return to the soak, and start up again the next day. (I tend to get overzealous and careless if I work a coin too much in one session)

This is a pretty advanced cleaning project, to be honest with you, and I am not sure that what lies beneath the green will be anything better than a pocked up moonscape, but you can at least give it a fighting chance by being a tad more gentle. Wink

Chris 



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Salus Populi Suprema Lex Esto - Missouri 1822

My gallery: http://www.forumancientcoins.com/gallery/index.php?cat=19691
oneill6217
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« Reply #5 on: October 22, 2011, 09:10:57 am »

Thanks Chris.  I ordered a sharp dental pick.  I know pliers are inappropriate  Roll Eyes.  Won't ever do that again.  I'll soak in in distilled water for as long as it takes and when my pick gets here I will manually remove the obstruction.  Thanks again!

Patrick
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casata137ec
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« Reply #6 on: October 22, 2011, 11:00:16 am »

No problem at all. Post progress pics and feel free to stop and ask questions if you feel the need! Smiley

Chris
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Salus Populi Suprema Lex Esto - Missouri 1822

My gallery: http://www.forumancientcoins.com/gallery/index.php?cat=19691
oneill6217
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« Reply #7 on: October 22, 2011, 11:27:31 am »

Hi Chris,

Here is a new pic, taken since I broke the edge and soaked it in olive oil for two days.  The coin is now in distilled water.  Since I am an archaeologist, I knew better than to use pliers on the coin...embarrassing.  I started to obsess on the coin and just stayed up too late I guess.  I plan to visit the lab this week and see what I can do there.  I will keep you informed!  Thanks!

Patrick 


Also, notice the filled appearance on the edge.  Is that fill, or is that the coin under the metallic-colored patina?  It looks like a thin layer of bronze over some white metal (lead?).  I will see if I cant test it at the lab, since it is already exposed by my mistake. 
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Salem Alshdaifat
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« Reply #8 on: October 23, 2011, 09:52:33 am »

hmmm
you didnt broke the coin, you broke the thick dirt, ithis type of dirt is always comes in two layers , white layer which is salty white sand from a close area to the sea, or to hot salted sand area like Jordan Vally, and then a thick mixed incrustation which is a reaction of engaging the salty sand and the coin metal, usually you will have a red incrustation under these layers, I hate this type of dirt, I would let it soak in white vinegar for three days at least, and then try again.
best.
Salem Alshdaifat
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oneill6217
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« Reply #9 on: October 23, 2011, 11:28:20 am »

Yay!  That is good to hear.  Vinegar will not damage the metal of the coin?
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Salem Alshdaifat
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« Reply #10 on: October 23, 2011, 12:09:59 pm »

this coin will need good care really, if you use hard acid for sure you will have damage on the surface of the coin where the thick incrustation is, take your time and make the dirt as soft as possible and keep taking the layers away till you reach the surface.
best.
Salem
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oneill6217
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« Reply #11 on: October 23, 2011, 12:26:56 pm »

Thank you Salem.  I appreciate the help

Patrick
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casata137ec
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« Reply #12 on: October 23, 2011, 01:08:15 pm »

I was hoping Salem would see this thread. He has worked hundreds (if not more!) of coins like this and would be the voice of experience on these.

...Since I am an archaeologist, I knew better than to use pliers on the coin...embarrassing.  I started to obsess on the coin and just stayed up too late I guess. 

lol...I hear you. As I said, I limit my cleaning time per coin for that exact reason. After seeing the pic I am glad you were mistaken and it was just crust broken off!.

Chris
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Salus Populi Suprema Lex Esto - Missouri 1822

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« Reply #13 on: October 23, 2011, 02:38:27 pm »

I would advice this but you have to be really careful, soak the coin for overnight on the white vinegar, take it out and while the coin is still wet (dont clean with water) knock on the edges with hard tool of metal, like big screw driver while the coin is on hard surface and standing, you have to be careful of how much power you knock, because you shouldent knock hard, you might break the coin, this will take lots of the dirt.
let me see the results!
best.
Salem
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oneill6217
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« Reply #14 on: October 25, 2011, 11:41:08 pm »

Hello all. Here is an update.  I used coarse rubber sand paper to take down the green nubbin in between distilled water soaks over the last few days.  The overall surface of the coin is much less gritty now (i did not touch any of it with the sandpaper).  I then worked on it with a scalpel last night and broke a piece of green off of the obverse surface, but not all the way through.  Details are beginning to show.  The deposit on the reverse is also worked down a bit with sand paper by hand.  I will stop soaking it in water and try the white vinegar as Salem has suggested.  Thank you for your help!  
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oneill6217
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« Reply #15 on: October 28, 2011, 03:10:25 pm »

UPDATE

Wow, Salem was right!  I tried white vinegar for about two hours and tapped the side as you instructed.  The coin is starting to look better.  Then I worked on the green blob with a scalpel and took it down some more on the obverse.  I nicked the right side on the obverse, but I think it must be the red dirt I broke and not the patina?  Here are some pics.  Should I continue the white vinegar bath?
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benito
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« Reply #16 on: October 28, 2011, 03:42:25 pm »

Some more acetic acid can do no wrong.
Once you are finished with the coin you can  use to convert freebase cocaine into cocaine acetate. Learned this in Peru.
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oneill6217
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« Reply #17 on: October 28, 2011, 03:58:00 pm »

lol
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oneill6217
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« Reply #18 on: October 30, 2011, 12:10:48 pm »

HERE IS ANOTHER UPDATE.

White vinegar bath for about 6 hours.

It's working!  I can read a few letters on the reverse now!  YAY!

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casata137ec
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« Reply #19 on: October 30, 2011, 02:23:27 pm »

lol, keep on rolling! Nice.

Chris
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Salus Populi Suprema Lex Esto - Missouri 1822

My gallery: http://www.forumancientcoins.com/gallery/index.php?cat=19691
oneill6217
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« Reply #20 on: October 31, 2011, 06:48:52 pm »

Woooooooooooooo Hooooooooooooooooo!  Almost there!

Anyone know what that lite colored spot in the middle of the reverse might be...looks like a break in the outer layer of the coin metal.  I ask again...is it filled with tin or something?
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« Reply #21 on: November 01, 2011, 02:41:27 am »

Wow!  What an incredible job! 

Salem's advice on this, and one or two other recent threads, about the use of vinegar on AE coins is very interesting.  I have not yet tried it but I am going to soon.  I have many coins that are in this condition (though not this quality) and come from the Jordan valley.

I have no clue what the white is.  I have a 26mm diameter coin of a later Ptolemy that is entirely made of lead and comes from Jordan but I have never heard of a bronze coated lead core before.  I am not even sure how that would work given the different melting temperatures.  You can fill a hollow bronze item with molten lead as was done with statuary.

Am I right in guessing that the orange colour is the bare metal while the red colour is an encrustation over the metal surface - the formerly green stuff?

Shawn

 
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SC
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« Reply #22 on: November 01, 2011, 02:55:30 am »

I have no clue what the white is.  I have a 26mm diameter coin of a later Ptolemy that is entirely made of lead and comes from Jordan but I have never heard of a bronze coated lead core before.  I am not even sure how that would work given the different melting temperatures.  You can fill a hollow bronze item with molten lead as was done with statuary.

Am I right in guessing that the orange colour is the bare metal while the red colour is an encrustation over the metal surface - the formerly green stuff?

Shawn

You often find lead in ancient copper and it does appear white. It seems to survive the melting process at least in small enough quantities to show it's characteristic white colour. As for other colours, these will be the full range of iron oxides and hydroxides and copper oxides and hydroxides. Iron oxides can of course be orange (rust). Between the lead, iron and copper compounds you have a almost a full spectrum of possible colours. Red, yellows, greens, oranges, purple's and with the most extreme copper turquoise shades, even blue.
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« Reply #23 on: November 01, 2011, 07:54:09 am »

Andrew,

Do you mean you often find lead inside AE coins?  This is new to me - though I don't know many areas like Republican AEs well.  What coin types does this apply to?

As for the other colours I was mainly trying to find out what is still on top of the surface (I think only the red) versus being the metal itself (I think the brown and orange).

It is interesting to see the changes in colour that occur with the use of vinegar.

Shawn
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SC
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oneill6217
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« Reply #24 on: November 01, 2011, 08:26:10 am »

Yes Shawn, that red color is a thin layer of very hard dirt!  I love this coin!  I tried white vinegar on a few other coins with mixed results.  It WILL strip patina so beeee careful.  I've been using it on some of my really crusty ones with some descent results.
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FORVM`s Classical Numismatics Discussion Board  |  Numismatic and History Discussions  |  Uncleaned Ancient Coin Discussion (Moderator: bruce61813)  |  Topic: How do I clean this wonderful Ptolemy coin without damaging it? « previous next »
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