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Author Topic: Bleaching agent made my silver coin all black!!!  (Read 10277 times)

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Offline Arya Aravand

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Bleaching agent made my silver coin all black!!!
« on: September 09, 2007, 05:00:10 am »
Hello friends. I have a silver parthian coin, that had some ugly dirts on it. I tried boiling in soda solution for some minutes, and the result was satisfactory but the dirt was not completely removed from the letters on the reverse, although I had employed a nylon brush several times. Afterwards I decided to use a a liquid detergent which is normally used as a bleaching agent (it contains Chlorine and smells very much). I soaked the coin in this liquid overnight. At the morning when I checked it out, I realized that the coin is now completely black!!! besides, I could observe some dirts removed from the coin and suspended in the liquid which I regarded it as a good sign. now the coin is in lemon juice but the black appearance is still observed. I'm sure that the coin is not damaged physically but probably the surface has been oxidized because of the chlorine. What do you suggest for restoring the silver shade? ( I should mention that I have a chemical metal polisher cream but I prefer to employ natural alternatives if there are any)     

Offline Robert_Brenchley

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Re: Bleaching agent made my silver coin all black!!!
« Reply #1 on: September 09, 2007, 08:31:59 am »
Don't polish it with cream whatever you do! Stop using strange concoctions on coins and stick to recommended methods. Silver coins turned black aren't necessarily bad, and if it was only in the solution overnight you probably did no damage. A scan would be useful, otherwise leave it, read through the threads here, and use the methods sugested.
Robert Brenchley

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Offline mwilson603

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Re: Bleaching agent made my silver coin all black!!!
« Reply #2 on: September 09, 2007, 08:37:25 am »
Don't polish it with cream whatever you do! Stop using strange concoctions on coins and stick to recommended methods. Silver coins turned black aren't necessarily bad, and if it was only in the solution overnight you probably did no damage. A scan would be useful, otherwise leave it, read through the threads here, and use the methods sugested.
Robert is absolutely right.  I would add that just to ensure no permanent damage or unwanted complications, I would now want to neutralise the chlorine.

Offline bruce61813

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Re: Bleaching agent made my silver coin all black!!!
« Reply #3 on: September 09, 2007, 11:42:08 am »
What the others have told you is true. You should have just let the coin soak for a couple days, and used something like a wood tooth pick if you wanted to dig everything out. Nothing works right way. The other  problem is, you are not working with pure alloys, there is a fair amount of copper and also lead, so modern silver cleaners can produce very unwanted results. Check through the other threads, this is the best advice.

Bruce
too many coins - too little time!!

Offline Arya Aravand

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Re: Bleaching agent made my silver coin all black!!!
« Reply #4 on: September 09, 2007, 12:06:37 pm »
Thank you so much friends for your useful advises. The below picture shows the coin before I soak it in the detergent. As you can see the observe is not that bad, but I just wanted to remove the dirts from the reverse, hence, making the letters and the monograms more visible. Unfortunately now I have a problem with my scanner, but as soon as I fixed it, I will post a picture of the coin in its present condition. However I should say that when I came back at home and checked the coin soaking in the lemon juice few minutes ago, I realized that most of the dirts have been removed and also the coin is  now rather gray, instead of being black! I think if it remains in this situation for one more night, all the dirts will be removed and the coin gets an acceptable appearance. Do you agree?

Offline Robert_Brenchley

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Re: Bleaching agent made my silver coin all black!!!
« Reply #5 on: September 09, 2007, 05:02:19 pm »
Leave it in the lemon juice and hopefully that'll fix it. The coin is a drachm of Orodes II, Sellwood Type 48, and should come up nicely with a bit of patience.
Robert Brenchley

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Offline bruce61813

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Re: Bleaching agent made my silver coin all black!!!
« Reply #6 on: September 10, 2007, 11:11:18 am »
Mix 2 teaspoons of lemon juice in 4 ounces of olive oil, and heat or warm at 150 deg F [about 70 C].
It is about the same as soaking in pure lemon juice, but the oil helps float the removed material away. I have found it to be effective, especially on solid silver coins. Coins of poor quality or highly debased, should be treated as if they are bronze or copper. but yours is good silver.

Bruce
too many coins - too little time!!

Offline Arya Aravand

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Re: Bleaching agent made my silver coin all black!!!
« Reply #7 on: September 10, 2007, 01:25:00 pm »
Thank you friends. I used the methods described above and now I'm eagerly waiting to see the results. The coin (which is now in the lemon juice mixture) seems to be much different from its first situation. I will pull it out few hours later and will post the results.

Offline bruce61813

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Re: Bleaching agent made my silver coin all black!!!
« Reply #8 on: September 10, 2007, 02:40:30 pm »
I would check it often, at least every 30 minutes, and scrub it with a medium soft nylon brush. That will remove the softened material and allow the acids to work on the newly exposed area. Don't soak it longer than is needed.

Bruce
too many coins - too little time!!

Offline Arya Aravand

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Re: Bleaching agent made my silver coin all black!!!
« Reply #9 on: September 10, 2007, 03:45:58 pm »
Thank you Bruce. Iam doing so. The influence of the acid was great, I think most of the dirts have been removed. there are just some of them with a red color remaining on the reverse, I think tomorrow I would get rid of them/.

Offline bruce61813

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Re: Bleaching agent made my silver coin all black!!!
« Reply #10 on: September 10, 2007, 10:08:49 pm »
Wonderful. I think I know the area you are talking about. It is heavily coated with clay, and maybe a combination of metal oxides.  If the acid combination hasn't broken it down, I would switch to a water, or water and soda soak for awhile.

The red is probably really hard clay, and sometimes just soaking it in water for a few days will help, too long an exposure to acid can etch a coins surface, and the copper mixed into the alloy is removed.

Bruce
too many coins - too little time!!

Offline Arya Aravand

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Re: Bleaching agent made my silver coin all black!!!
« Reply #11 on: September 11, 2007, 01:15:27 pm »
As you can see, the result is unbelievable!!. After I took the coin out of the Lemon juice, I realized that the dirts become so loose. Then I used Soda solution and a nylon brush to wipe out the remaining. Here is the the coin in its present conditions. When I look at the coin now, hardly can I believe that this is not a modern one! I wonder what would I do if the seller showed me the cleaned coin. Would I buy this? I'm not so sure! How should I distinguish between this and a fake one, regarding the fact that there is nearly no signs of any observable wear on the coin. The  only thing that I was thinking about was its rough surface. I think this remains as the most important evidence. Do you agree?!
However, this one turned out to be one of the most beautiful coins of mine thanks to your useful advices. Now I can see that there is no need to the chemical polishers! Thank you very much again friends.

Offline bruce61813

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Re: Bleaching agent made my silver coin all black!!!
« Reply #12 on: September 11, 2007, 01:32:47 pm »
The roughened surface is from the copper that was probably leached out. Let the coin sit in the sun far a week or two and it should start to dull a bit. That is one of the problems with pure lemon juice, it tends to shine coins a little too much. But it came out fine otherwise.

Bruce
too many coins - too little time!!

Offline Raymond

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Re: Bleaching agent made my silver coin all black!!!
« Reply #13 on: September 11, 2007, 02:04:51 pm »
would a sharpened Bamboo skewer or chopstick be used to pick away at the remaining red areas?
Terific coin by the way
Raymond
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Offline bruce61813

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Re: Bleaching agent made my silver coin all black!!!
« Reply #14 on: September 11, 2007, 04:29:01 pm »
It is just red clay, I would leave it, as it does not harm the coin, and was part of the original crusting. If the original had not been so thick over that portion of the coin, it could have been left.

Bruce
too many coins - too little time!!

Offline Arya Aravand

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Re: Bleaching agent made my silver coin all black!!!
« Reply #15 on: September 11, 2007, 04:42:24 pm »
Thank you Bruce, I will put the coin in front of the sun, because I don't feel much comfortable when it is too shiny. About the red blocks, I used toothpick several times, before and after final washing with soda solution. It picked away some of them but to remove all others, I think I had to wait more and I didn't want my coin to stay in lemon juice anymore.
About the picture, NO! I didn't paint the coin whatsoever! I'm not that cruel! I used just some photoshop tools to get some idea about the king Orodes-II 's face. I put it here because I thought may be some of you (like me!) are interested to see that. isn't it funny? (May be I am wrong about his hair color, but the king-his majesty- may forgive me!)

Offline awl

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Re: Bleaching agent made my silver coin all black!!!
« Reply #16 on: September 11, 2007, 09:14:17 pm »
Very nice job cleaning. I almost got scared for a second with the colorized picture!

Offline Howard Cole

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Re: Bleaching agent made my silver coin all black!!!
« Reply #17 on: September 12, 2007, 05:01:32 am »
I think we can start a new market by colorizing ancient coins.  Sort of what they have done with modern coins, like the US state quarter series.

Offline bruce61813

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Re: Bleaching agent made my silver coin all black!!!
« Reply #18 on: September 12, 2007, 12:02:30 pm »
Well they used to paint statues in ancient times to make them look life-like, so why can't we colorize coins. [tongue firmly in cheek!] But it is any interesting sight.

bruce
too many coins - too little time!!

Offline Arya Aravand

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Re: Bleaching agent made my silver coin all black!!!
« Reply #19 on: September 12, 2007, 05:24:46 pm »
It was not much observable when the coin was uncleaned. but what is that on his neck? is it some part of his garment? (I mean the thing that is like a worm!)

Offline Howard Cole

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Re: Bleaching agent made my silver coin all black!!!
« Reply #20 on: September 12, 2007, 05:40:57 pm »
This is a coin of Orodes II, 57-38 BC, minted at Ecbatana.  On the neck is a torque that ends in a seahorse.  This is listed in Sellwood's book as number 48.6.

Offline Arya Aravand

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Re: Bleaching agent made my silver coin all black!!!
« Reply #21 on: September 12, 2007, 05:47:42 pm »
OH yesss, I remember "seahorse" I once saw in Sellwood, but I didn't pay much attention to it! But I think the coin is Sellwood type 48.9. Am I right?

Offline Howard Cole

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Re: Bleaching agent made my silver coin all black!!!
« Reply #22 on: September 12, 2007, 06:08:15 pm »
No, it is 48.6 with anchor i.  48.9 has anchor iv, which has something that looks like a capital E on its side pointing up.  I don't see this E on your coin above the anchor.  You have the start of the second line of inscription above the anchor, which is a square O.

Offline Arya Aravand

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Re: Bleaching agent made my silver coin all black!!!
« Reply #23 on: September 13, 2007, 01:30:52 pm »
Howard, I actually can not see any difference with the type 48.9. I do not understand what do you mean exactly by the E, but when I compare the two, the coins seem to be completely similar. Moreover, where did you see the Sellwood type 48.6?! May be in its book since there is no such a type in the parthia.com:
http://www.parthia.com/orodes2.htm#Type_48

Offline Howard Cole

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Re: Bleaching agent made my silver coin all black!!!
« Reply #24 on: September 13, 2007, 06:39:15 pm »
Hi Arya,

Yes, the reference is from a book.  The standard guide Parthian coins is David Sellwood's An Introduction to The Coinage of Parthia

You coin lacks any symbol above the anchor, so it is Sellwood 48.6.  I have circled the symbol above Sellwood 48.9 at Parthia.com.

Offline Arya Aravand

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Re: Bleaching agent made my silver coin all black!!!
« Reply #25 on: September 14, 2007, 03:39:09 am »

Offline Howard Cole

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Re: Bleaching agent made my silver coin all black!!!
« Reply #26 on: September 14, 2007, 04:44:43 am »

Offline Arya Aravand

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Re: Bleaching agent made my silver coin all black!!!
« Reply #27 on: September 14, 2007, 07:56:21 am »

 

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