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 Replies: 13 / Views: 2,120 |
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Valued Member
United States
190 Posts |
I just picked up a 1949 Canada Small Cent in nice BU Rec condition, except that it has been shellacked with varnish. How do I remove the varnish from the coin without damaging the BU Red surfaces? I know you can use alcohol and Acetone to remove varnish, but will those chemicals cause my con to turn brown? I will leave it shellacked if removing it will damage the red color.
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Moderator
 United States
56855 Posts |
100% pure acetone? John1  |
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Rest in Peace
United States
18456 Posts |
 Acetone will not damage your coin .  |
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Moderator
United States
188052 Posts |
Acetone should be safe to use.
I believe you should avoid using the acetone in direct sunlight if the coin is red uncirculated.
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Bedrock of the Community
United States
94367 Posts |
It can be dissolved with denatured alcohol as well.  Edited by Coinfrog
10/10/2019 12:09 pm
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Moderator
Canada
10456 Posts |
Toluene works too, and does not photochemically react with copper like acetone does.
"Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy eBay store
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Pillar of the Community
 United States
7936 Posts |
It depends on whether the coin has been varnished or shellacked. They are different substances and require different solvents.
Varnish is removed by nonpolar solvents like toluene or mineral spirits, which you might already have around if you ever use oil based paints. I would start there.
If that doesn't work, shellac is removed by alcohols (methyl or denatured).
If acetone is a potential problem as mentioned, this sequence would avoid it.
Edited by tdziemia
10/10/2019 5:45 pm
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Pillar of the Community
United States
1005 Posts |
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Bedrock of the Community
United States
20753 Posts |
Quote:
Thank you for mentioning the photochemical breakdown of acetone on copper catalyst, SPP; this seems to be very new research I was not aware of I've heard this rumor in the past. I tried Acetone on Copper coins and in direct Sunlight. I've put Copper coins in a glass and even soaked it in direct Sunlight for days. Nothing happened at all. Of course the people that say this may be using a different Sun. Just use pure Acetone and let us know how it worked out. |
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Pillar of the Community
United States
3468 Posts |
Quote:
Of course the people that say this may be using a different Sun  |
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Bedrock of the Community
United States
17884 Posts |
Quote:
Toluene works too, and does not photochemically react with copper like acetone does. But if you are not use to it the very strong odor of toluene is rather objectionable. The reaction of strong sunlight and copper is real, but if you are able to read the report you will find they used very strong sunlight for an extended period and the resulting reaction products on the copper were microscopic. Yes the reaction can happen, but it really isn't something I would worry about. Oh and the test were run on pieces of copper with freshly exposed surfaces (think sanded). |
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Pillar of the Community
United States
4618 Posts |
This may sound like common sense advice, but make sure to read all of the cautions on any of the chemicals listed above. These can cause not only health problems, but pose a potential fire or explosion risk as well. Don't take the warnings for granted. I had a next door neighbor use something they shouldn't have as a cleaner and caused a fire.
ANA ID: 3203813 - CONECA ID: N-5637 Clean a coin that may be worth collecting? Please DON'T! When in doubt, leave it dirty!! 
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Pillar of the Community
United States
7936 Posts |
@yokozuna, that is a VERY good point.
I know that writing in caps is rude, so I won't do that, but the risks are:
- all of the materials mentioned here are highly flammable!
- acetone has a very low flash point, which means even the air around it can ignite, if not used in a well ventilated space!
- toluene is somewhat toxic. It is the active agent that gets people high when they huff (sniff) glue. Overexposure can give central nervous system or respiratory issues.
Edited by tdziemia
10/11/2019 1:37 pm
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Valued Member
 United States
190 Posts |
The general definition for shellack is coated with varnish, I did not realize there was some other kind of coating out there. This is a clear coating that left a few bubbles and is pealing where it was not applied as well. At some points it is not clear and kind of a brownish color. The coin is a 1949 "A to Denticle" BU Red. Would it be better to leave it shellacked or to strip it off and encapsulate? How long must I let it sit before putting it inside a plastic coin protector with a foam insert? I am willing to leave it shellacked or varnished, as long as this will not damage the coin by leaving it that way. I also have thought about sending it into NGC to be graded and slabbed and I do not want it to come back cleaned or marked as being Laquered.
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Replies: 13 / Views: 2,120 |
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Posted 10/10/2019 11:42 am
