My Acetone experiment with pictures and questions

Hi,

I am afraid that this topic has already been beaten to death...... But to a newbie like myself, it is a fascinating adventure. I did read some posts in CT before I became brave enough to go to Home Depot for a small can of Acetone.

This week I bought this 1914 Chinese silver dollar on eBay at a very reasonable price. It is 39mm in diameter and should be .890 silver. It looked like this when I received it:



It looked kind of dirty to me, with all the brown and blue stains. I put the coin into distilled water for 1/2 hour and in Acetone for 3 hours. After that I took it out and let it air dry for 10 minutes.

Now it looks like this:



My questions:
1. The brown and blue "stains" are still there. Does it mean that both the brown and the blue are NT?

2. Will keeping it in Acetone overnight possibly result in better or harmful effects on the coin?

3. For this coin, should I stop right here? Or is there anything else I can do to "conserve" the coin better?

Thanks.

 

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I would stop there. Acetone will do nothing more to help this coin.
I feel anything else you do, will harm it.

 

Acetone is used to remove foreign materials from coins such as grease, oil, glue, dirt, etc.
What you have on your coin is the result of natural toning, i.e., the reaction of the coining metal and the environment.
Like Larry said, anything you do to it from now on will be detrimental.

 

Great post! I am thinking about using some acetone myself on some Canadian Siliver Maple leafs that have something that looks like water spots on them. I just got them a few weeks ago but they are from the late 1980's.

Let me the get the procedure straight.

1. Dip in acetone for a few minutes
2. Let stand in distilled water a few more
3. Air dry

 

Instead of "2. Let stand ..." I personally would rinse (pour water over).

"Air dry" is okay as long as you have true distilled water.
Patting dry with a clean, lintless cotton towel (like a dish towel) is also acceptable.
Notice I said patting, not rubbing.

 

Thanks for the answers.

The reason I wanted to work on this coin was that there was a lot of yellow and brown on the coin that looks like stain or "rust", which made the coin quite unpleasant to look at.

So, is the brown and yellow stain actually natural toning? Or was it some sort of chemical reaction on the coin caused by alien material that Acetone cannot remove?

Please let me know more. Thanks.

 

It's not the "normal" expected toning but it still is the result of the environment and the coining metal chemically reacting.

 

I suspect the toning is by the traditional NT environment, but both NT and AT are the same chemical reactions so NO chemical or other process can separate them.

Also do not rinse with water after acetone, you just reverse some of the good you did. Acetone will remove residual moisture, and air dries very quickly, and should be the last step. Rinsing with water after that just adds moisture back into the chemical reaction process, and since the acetone air dries, no need for cloth contact.

 

Good point.
I'll have to keep this in mind.

BTW, the same doesn't apply to isopropyl (rubbing) alcohol, at least not the 70-75% stuff you get at the drugstore.

 

Is anyone else interested in seeing the other side of the coin and the reeding? You might want to check the coin's weight and confirm that it really is .890 silver. The denticles look good and there is nothing that makes me think it is a fake except that dark toning is something that I have seen applied to fakes.

 

Yes, I agree, but for those extremely afraid of using acetone, Walmart for one sells 91% isopropyl in their surpercenters, at a very low price. It is not as good as acetone, but much better than water or 70% isopropyl for coins.

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Now you are making me nervous. I found a kitchen scale which narrows the weight of this coin down to 27-28g, which seems to be right.

Here are pictures of the other side. So, is it a fake?

BEFORE acetone:



AFTER acetone (all yellow and brown around with a spot of blue on top):

 

Sure, no problem, but I have not seen that unless contaminated or reused acetone was the cause. But I am relying on chemical properties that says within normal conditions ( temp,pressure, humidity, etc) pure acetone will evaporate 100% and any material left on the coin was contaminants dissolved/suspended in the acetone to start with.

Jim
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There is no reason to be nervious. It looks like you have a good coin.

I guess that I look at a coin & start by determining if it is authentic. Then, I turn to problem diagnostics (hairlines, polishing, tooling) & then finally to the grade. The denticles on both sides of your coin are well defined and from what I can tell from the photos, you have a genuine piece.