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 Replies: 19 / Views: 2,684 |
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Pillar of the Community
 Lebanon
506 Posts |
It is a surface from the paper itself that sticked on it ,Is it safe to use acetone on bronze ? Because it is a bronze medal.
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Pillar of the Community
United States
5825 Posts |
Quote:
That looks more like verdigris than PVC damage, in which case acetone won't help. It certainly doesn't hurt to try that first, but I suspect it won't do anything. Start one step at a time with what would do the least harm to the medal if it were the wrong treatment. 1. Acetone 2. Soap, distilled water and VERY gentle manipulation with a Q-Tip. 3. Wait for further suggestions. |
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Pillar of the Community
United States
574 Posts |
The only thing I'd add to the discussion is that the proper order of solvents to try in order of polarity is:
1. Distilled water
2. Acetone
3. Xylene
All three are safe for use with bronze, but sadly if the reaction is PVC related, which appears likely, none of these will effectively remove it. Verdi Care is a product that has some effectiveness against PVC residue but is sometimes difficult to find.
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Bedrock of the Community
United States
10038 Posts |
Although I have no personal experience with it, I have read on this forum that copper coins could pick up a slight pink tint when acetone is used IN DIRECT SUNLIGHT. Otherwise acetone is safe. I understand bronze is an alloy, but just thought I would mention this.
Personally I would try the hot soapy water, then acetone, then xylene.
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Pillar of the Community
1110 Posts |
Quote:
It is a surface from the paper itself that sticked on it This isn't paper.  |
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Bedrock of the Community
United States
94367 Posts |
What shows on the medal's surface looks much different than the color of the cloth. I fear that moisture accumulated between the surfaces, creating a corrosive chemical reaction with the copper.
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Bedrock of the Community
United States
20753 Posts |
Not sure what is available over there but if you can find Acetone, try that first. However, there is a good chance the damage is done to the metal so in that case not much can help. Quote:
Although I have no personal experience with it, I have read on this forum that copper coins could pick up a slight pink tint when acetone is used IN DIRECT SUNLIGHT. Otherwise acetone is safe. I understand bronze is an alloy, but just thought I would mention this.
Personally I would try the hot soapy water, then acetone, then xylene. for one thing, never, ever use soapy water. With out knowing what that water really is you could end up with even more damage. And that old wives tale of how Acetone effects Copper. I read that same silly stuff a long time ago. I put Copper coins in a jar filled with Acetone and put it in direct Sunlight for a few weeks. Nothing happened. Maybe I was using the wrong Sun.  |
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Pillar of the Community
Lebanon
506 Posts |
@coinfrog I think you are right ,because the cloth was on the medal found with rot on its box.
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Bedrock of the Community
United States
17884 Posts |
The one thing that worries me is the medal appears to have a surface treatment such as a lacquer or other coating that may react with the acetone.
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Pillar of the Community
Lebanon
506 Posts |
Edited by chronos
10/20/2020 05:29 am
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Bedrock of the Community
Australia
21788 Posts |
It seems to me that the soft sponge cloth that has been in contact with the medal, and was enclosed with the coin in the box, may have had some moisture in it.
Some of that green tinge looks like minor verdigris damage.
I can only agree with some of the suggestions so far, that have been put forward:
1. gentle rubbing with a Q-tip dipped in acetone,
2. gentle rubbing with a Q-tip soaked in distilled water, then dry thoroughly.
If it is verdigris, neither of the above treatments will help much.
If it is verdigris, it may be worth doing a Google search on how museums conserve and protect copper and bronze objects that have been affected by verdigris attack. there will be risks in whatever procedure you may adopt.
Potential risks involving verdigris passivation may deter you from adopting any of the suggested museum procedures.
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Pillar of the Community
1110 Posts |
That what I was afraid of, baked into the surface.
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Bedrock of the Community
United States
94367 Posts |
Surface appears etched, as feared. This is pretty much a goner.
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Pillar of the Community
 United States
5675 Posts |
Since most of that green came off with acetone, it's likely PVC damage from the foam wrapper. The PVC corroded the surface below the green spots, and there's nothing you can do to salvage that. That white residue is probably left over from what was dissolved in the acetone. If I were you, I would probably soak the entire medal in acetone for a few minutes, then rinse in acetone again to get rid of the residue. You'll be left with many tiny spots of corrosion, but at least it won't be green or white.
And make sure the acetone you're using is pure acetone.
Edited by Zurie
10/20/2020 1:10 pm
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Pillar of the Community
United States
1667 Posts |
that insert is a plasticized foam. I really would have started with distilled water soak and then rolling cotton swabs across the area gently trying to pick up the green.
And only moved to acetone if that didn't get anywhere. My concern is there is a finish over the bronze the coin the acetone (a solvent) might deteriorate.
now that you've removed some green, it appears pitted where the green was. there's no fixing that unfortunately. you can stop it from getting worse, that's about it, the damage is done.
Edited by Big-Kingdom
10/21/2020 3:48 pm
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Replies: 19 / Views: 2,684 |
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Posted 10/17/2020 10:18 am
