Author Topic: Acetone dips  (Read 6173 times)

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Offline PandaCollector

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Acetone dips
« on: December 12, 2010, 06:32:55 AM »
Check out the photos and discussion of acetone treatment for coins:
http://forums.collectors.com/messageview.cfm?catid=6&threadid=759848

Best wishes,
Peter Anthony
http://www.pandacollector.com

Offline badon

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Re: Acetone dips
« Reply #1 on: December 13, 2010, 10:57:22 PM »
If I have any problems with NCS, I might start conserving coins myself. I have quite a lot of experience with acetone (and MEK) treatments of metals, which ought to give me a leg up on a project like this. I just want to add that you have to use pure acetone. Most store bought acetone has some percentage of water in it. That's what might cause you a surprise if the water does something to your coin when the final, clean acetone dip dries.

Also, the fellow in the posting you linked to likes to blast his coins dry with compressed air. That's a good idea, but only if you can be sure it's very clean, dust free air. Otherwise, the dust particles may ping themselves off on your coin's surface like a rock on a windshield, and turn any 70's you may have into instant 69's.

And, on final thought: Acetone is about as flammable as household product get. Be very careful, and make sure your work area is well-ventilated. The fumes from the acetone are flammable too, and they can ignite with the flick of a light switch - not to mention doing bad things to you when you breathe it in.

Offline IloiloKano

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Re: Acetone dips
« Reply #2 on: February 23, 2012, 07:15:37 PM »
The link referenced above to a Collectors Universe forum post was deleted, and it is only visible now via use of a technique where the user is put in reply mode.

Why was it deleted? Well, I believe it was because the PCGS President got his feelings hurt through a private message sent by the originator of the post, and since banning the forum member wasn't enough, he threw a fit and deleted access to a very useful forum post created by that former forum member.

I am that former forum member.

Anyway, here are links to the four pages of that forum thread, starting with the first page.
http://forums.collectors.com/messagepost.cfm?postaction=reply&catid=6&threadid=759848&messid=9704774&STARTPAGE=1&parentid=9704774

http://forums.collectors.com/messagepost.cfm?postaction=reply&catid=6&threadid=759848&messid=9704774&STARTPAGE=2&parentid=9704774

http://forums.collectors.com/messagepost.cfm?postaction=reply&catid=6&threadid=759848&messid=9704774&STARTPAGE=3&parentid=9704774

http://forums.collectors.com/messagepost.cfm?postaction=reply&catid=6&threadid=759848&messid=9704774&STARTPAGE=4&parentid=9704774

Offline badon

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Re: Acetone dips
« Reply #3 on: February 23, 2012, 08:18:58 PM »
If you want your effort to be permanently available for everyone, maybe there's a place for such how-to guides on the Coin Compendium. That's not the primary purpose of the Coin Compendium, but maybe it can be accommodated. I'll give this some thought. You may want to save those pages before they disappear forever.

Offline Gilmore

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Re: Acetone dips
« Reply #4 on: February 23, 2012, 08:48:04 PM »
Very interesting, and amazing results. Are acetone dips safe to use on gold, silver and silver proofs also?
What about toning? How can toning can be removed?

Offline IloiloKano

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Re: Acetone dips
« Reply #5 on: February 23, 2012, 09:21:25 PM »
Are acetone dips safe to use on gold, silver and silver proofs also?
What about toning? How can toning can be removed?
Acetone will not react with any metal, nor will it affect toning.

It is safe to soak any coin in acetone, but you must exercise care in what you do after taking it out of an acetone soak. Personally, I would be extremely careful with any proof coin, as even the slightest hairline can significantly reduce value. So I wouldn't even blot a proof coin dry. Instead, I would allow the acetone to thoroughly evaporate without intervention. I wouldn't even use a blast of compressed gas. Acetone will evaporate from the surface of a coin very quickly (a matter of mere seconds).

For NON-proof coins, I am comfortable with light blotting with a cotton ball, though I'd prefer to not even do that. Others may be comfortable with light wiping, but I would advise against it.

I personally don't recommend removing toning, but when toning is "ugly" in appearance, I am not critical if others choose to remove it. I've seen silver toning removed where the result was rather pleasing, but I primarily collect bronzes, and I have never seen even one example where removing of toning from a bronze coin didn't destroy it's value.

So I will not offer any suggestions as to how toning might be removed, but if you choose to try it with your own coins, I'll not criticize you for it.

Offline badon

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Re: Acetone dips
« Reply #6 on: February 23, 2012, 09:26:30 PM »
Air drying of acetone can leave residues on the coin, especially if you're cleaning more than one coin with it. Instead, I recommend rinsing the acetone off of the coin with deionized water (distilled water). I don't conserve my coins myself, but if I remember correctly, someone said the coins should be rinsed in either acetone or deionized water after being dipped for toning removal, to ensure the toning remover doesn't leave blotches and drip marks on the coin.

Offline Gilmore

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Re: Acetone dips
« Reply #7 on: February 23, 2012, 09:51:56 PM »
Personally, I would be extremely careful with any proof coin, as even the slightest hairline can significantly reduce value.

Years ago when I was new to coin collecting I've experienced that while trying to conserve one of my coins for the first time. The coin was damaged as I had no idea how easy it is to scratch the proof surface. I have not done it ever again but use NCS service now.

IloiloKano, looking at the excellent results you achieved I am tempted to try it again. I will not try it on a proof coin though and will follow your instructions.

Regarding toning, I asked NCS to remove toning from a few silver proof medals I submitted on January. 2-3 weeks after I received the medals they started to develop rust spots on the areas were the toning was present before. Using a loupe these spots look black/dark-grey with brownish areas inside them. I still find it hard to believe how fast it developed. These medals are now doing their way back to NGC. Is it safe to remove toning from a silver proofs or I was just lucky?

Offline Panda Express

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Re: Acetone dips
« Reply #8 on: February 23, 2012, 10:13:14 PM »
Very interesting, and amazing results. Are acetone dips safe to use on gold, silver and silver proofs also?
What about toning? How can toning can be removed?

Great post regarding acetone treatments.  I will certainly keep this on file for future references.  If you have old silver bullion with little to no numismatic value, laying a small piece of tin foil in a glass bowl. Place the old tarnished silver bullion on the tin foil. Add 10 ml of baking soda and an 1 ml of salt (one pinch) and poor warm to hot water in the bowl. The hotter the water, the reaction is faster to remove the toning on the silver coin.  With regards to gold bullion with no numismatic value that has copper spots, I use 61.4% Nitric acid soaking the coin for several minutes in a clear pyrex bowl. I follow this up by a distilled water rinse and this removes all copper spots.  I don't recommend you use these methods on proof or numismatic coins.  I usually send them in to NCS for conservation. 

Offline SANDAC

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Re: Acetone dips
« Reply #9 on: February 23, 2012, 11:17:47 PM »
I have a bag of grimmy Peace Dollars so I did some experiments with them first.  I settled down to a two-stage process where I would soak the coin for 24 hours in one bottle (empty baby food glass bottle works great), and then rinse it in the 2nd bottle and set on its edge to dry.  If you are proficient with chopstick you can modify a pair of wooden chopsticks and grabe the coin by its edge.  After I'm comfortable with the process, I tried it on my roll of 1934 Junk dollars before sending them to NGC.  It works out great.  I wouldn't try this on proof coins.  Those I leave to the professional.

Offline PandaBrian

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Re: Acetone dips
« Reply #10 on: February 24, 2012, 12:09:12 PM »
Acetone is effective for many conservation efforts.  Generally, it's not a bad a idea to give a coin that may or may not have been in soft plastic at some point a quick dip in acetone.  PVC residues aren't immediately visible and develop the milky and greenish colors over time. 

If done properly and thoroughly you shouldn't need to rinse acetone off of the coin.  Acetone is a drying agent and evaporates quickly.  If you are getting spots after using acetone, you probably need fresh acetone.  Acetone and Denatured Alcohol are commonly used in conservation as drying agents.
Brian Silliman
Senior Numismatist
Panda America
Brian@PandaAmerica.com
www.PandaAmerica.com

Instructor: ANA Coin Grading & Counterfeit Detection Seminars.
Former NGC Authenticator & Grader, NCS Conservator and ANA Authenticator

Offline comeaux

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Re: Acetone dips
« Reply #11 on: March 02, 2012, 06:38:42 PM »
What affect will acetone have on the coin being graded?

I have seen some coins come back from NGC as “harshly cleaned”

I’m going to experiment with junk coins to see what results are obtained. 

Thanks !

Offline badon

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Re: Acetone dips
« Reply #12 on: March 02, 2012, 08:05:19 PM »
By itself, acetone is harmless to coins. The only exception to that might be in the case of colored coins. The acetone might dissolve the coloring on the older types. The enameled ones should be OK, but I wouldn't want to be the first to try it - I'd let NCS do it.

Offline IloiloKano

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Re: Acetone dips
« Reply #13 on: March 02, 2012, 08:16:24 PM »
What affect will acetone have on the coin being graded?

PCGS graded the coin the first page of the forum thread referenced above as MS64BN, which immediately made my $90 purchase worth more in the $300 neighborhood.

It's now in my PCGS Registry Set here: http://www.pcgs.com/SetRegistry/publishedset.aspx?s=46218

So if you do it right, (read all four pages of the forum thread - there's good reliable information there), an acetone dip will not prevent a coin from being graded, though other unrelated factors may.

Offline SANDAC

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Re: Acetone dips
« Reply #14 on: March 02, 2012, 08:44:58 PM »
I've submitted 10 acetone-treated 1934 Junk coins to NGC now.  Four of them received MS65 grade and the other were various grades from MS62 to MS64.  None of them received a Detailed grade.  So at least my experience is that acetone dip is not considered "cleaned".