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Author Topic: IMP C P LIC VALERIANVS AVG - RESTITVT ORIENTIS  (Read 2218 times)

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Offline Batista

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IMP C P LIC VALERIANVS AVG - RESTITVT ORIENTIS
« on: March 24, 2017, 10:22:38 pm »
Hi guys,
Just received this Valerianus I AR Antoninianus but it's all crusty...Has you can see in the pictures it has various types of incrustrations...Green, yellow and brown...The coin has nice detail but its all stained with corrosion.
The yellow corrosion can be removed just with a tootpick...the green corrosion is a little harder but the brown corrosion just doesn't get out.
Has you can see in the pictures the crusts are on top of the coin.

Can I clean this coin? How? What do you think?


Offline SC

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Re: IMP C P LIC VALERIANVS AVG - RESTITVT ORIENTIS
« Reply #1 on: March 25, 2017, 10:20:29 am »
The yellow is just dirt if it is coming off with toothpick.  Keep removing.

The green looks like hard malachite encrustations caused by cooper residue leached out of other items in the dirt near the coin.  They could be shaved off of a bronze coin wit a scalpel but on silver only chemical treatment will do as you don't want to scratch the silver.

The brown, which is a hard iron or copper deposit, will also need chemical treatment.

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(Shawn Caza, Ottawa)

Offline Robert_Brenchley

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Re: IMP C P LIC VALERIANVS AVG - RESTITVT ORIENTIS
« Reply #2 on: March 25, 2017, 06:02:23 pm »
Valerian ants typically have a low silver content, so treat it as copper. If it looks silver, it's one of the 'better' ones as far as the metal goes, or is it silvered copper? I can't be completely sure from the pics.
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Offline SC

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Re: IMP C P LIC VALERIANVS AVG - RESTITVT ORIENTIS
« Reply #3 on: March 26, 2017, 09:39:32 am »
Even though the silver content is getting low, I personally still treat all Valerian coins, and those of Gallienus up to around 262 AD, as silver in terms of cleaning.  That is I assume they will scratch from mechanical cleaning more like a silver than a bronze coin, and I assume that chemical treatments will react as silver rather than bronze. 

Shawn

 
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(Shawn Caza, Ottawa)

Offline Batista

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Re: IMP C P LIC VALERIANVS AVG - RESTITVT ORIENTIS
« Reply #4 on: March 26, 2017, 09:21:36 pm »
Thank you for your responses otlichnik and Robert_Brenchley.

After watching the coin carefully with a magnifying glass 15x, it looks to me as the corrosion is all on top of the silver...So it can be extracted.
I think, and in books it says, the coin is Silver but it has less silver than usual...Its better than a rich billon but worse than a denario.

otlichnik what chemical treatment do you advice? Amonia? Baking Soda? citric acid?

Cheers

Offline SC

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Re: IMP C P LIC VALERIANVS AVG - RESTITVT ORIENTIS
« Reply #5 on: March 28, 2017, 06:12:22 pm »
I rarely clean silver.  I have used both vinegar and lemon juice for short soakings (sometimes the whole coin - sometimes just drops on one part).  But these have always been for better silver - i.e pre-249 AD.

If I were you I would start with lemon juice drops on the coin in short time frames.  But I would read more first.  Maybe you can find a post where people have tried to chemically treat a Valerian or Gallienus...

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(Shawn Caza, Ottawa)

Offline Batista

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Re: IMP C P LIC VALERIANVS AVG - RESTITVT ORIENTIS
« Reply #6 on: April 25, 2017, 08:16:14 pm »
So a month has passed.

I cleaned the coin very carefully, with soaking in DW and 2 times with a mild solution of DW+ 5% to 10% Citric acid (Powder).
Then last week I did the electrolytic reduction with a dilute citric acid solution (80% boiling DW and 20% lemon juice) for some 5 minutes... That was the only time I saw some of the rust colored deposits leaving the coin.

This Is how the coin is now...Not very different. The biggest difference for me is the green deposits. Some disappeared completely and others shrank significantly.
The Yellow deposits also disappeared but those where soft and you could take them out with a toothpick.

My next cleaning move is still in planning...




Offline SC

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Re: IMP C P LIC VALERIANVS AVG - RESTITVT ORIENTIS
« Reply #7 on: April 26, 2017, 05:54:59 pm »
You could get more of the green off by putting citric acid on just those parts.  make up your solution then apply yo those parts with a q-tip.  Leave for 15 minutes then rinse whole coin off in DW.

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Offline B-Chicago

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Re: IMP C P LIC VALERIANVS AVG - RESTITVT ORIENTIS
« Reply #8 on: May 17, 2017, 11:38:55 am »
the red/brown stuff does eventually weaken and break down in DW but it often spreads around - with that coin I would try a boil in water w coin wrapped in tinfoil and or a few short baths in vinegar followed by brushing with a softer toothbrush


Offline Batista

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Re: IMP C P LIC VALERIANVS AVG - RESTITVT ORIENTIS
« Reply #9 on: May 31, 2017, 07:31:19 pm »
Brian, you would boil the coin for how long? The tinfoil its the shinny part faced in or out? I'm getting frustraded with this coin.
I can't believe that it's not possible to remove something attached to the coin.
On the last treatment with acitric acid and hot DW, the coin gained some redish spots...2 or 3...and I don't know what that is.

Detail of corrotion stuck to the coin:









Is it even possible to restore this coin? Your sincere opinion.

Thanks to all for their help.
Luis

Offline B-Chicago

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Re: IMP C P LIC VALERIANVS AVG - RESTITVT ORIENTIS
« Reply #10 on: June 01, 2017, 11:40:35 am »
5-7 minutes up to 10? - rinse and repeat in future if want to try again - tinfoil will break down and that's when you know it wont do any further improvement

it does work on nasty stuff stuck to silver some of the time and seems to break down the red brown crusty gunk - could take several tries - soak in distilled water for a few weeks between boiling if it looks like it is working


the other more invasive option is to make a paste out of baking soda and rub with fingers - may try that after trying short vinegar bath but remember copper content is high so acidic options are best left to use as last resort as they can and will eat the copper away




Offline Joe Sermarini

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Re: IMP C P LIC VALERIANVS AVG - RESTITVT ORIENTIS
« Reply #11 on: June 01, 2017, 02:53:34 pm »
It is perfectly OK as it is right now. It does not need "restoration." Is it possible to clean it further? Possible, yes. Worth the effort it will require, no.
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