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ozjohn

Cleaning

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I was watching the news today concerning a hoard of medieval coins recently discovered by metal detectors in SW England. The commentary  went on to say that they had been cleaned by conservators of the British Museum. Which raises an interesting question. When should a coin be cleaned and when shouldn't be cleaned? The coins when they were discovered were filthy (not unexpected as they had been buried for the best part of a thousand years) nevertheless they were cleaned by expert conservators and this action must impact on the coins in some way.

Given the cleaning of these rare coins has taken place and seems to be standard practice for ancient coins why does cleaning of more modern coins attract such negative comment on theseforums given any cleaning performed is performed with minimum impact of the coin ie only dirt and ugly tarnish is removed from the coin's surface as what has occurred with this hoard. Insteadany suspicion of cleaning seems to brand a coin for life often on the flimsiest of evidence as the coin cannot be examined properly from a photo or scan. As I have said before any high grade coin George V coin that has been put aside for close to hundred years or more and probably tarnished (toned ) during this period. Sometimes it becomes so bad that it detracts from the coin and cleaningwill enhance the coin's appearance and hopefully it's value. Of course the decision to clean or not to clean is a decision not to be taken lightly and my advice would still be if in doubt then don't. I still maintain that any bright hundred year old coin has probably been cleaned at some time in that period.

 

Edited by ozjohn
poorly justified

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I am not sure if you are asking an opinion or making a statement 🙂

Most coins you can find so have a choice, you can buy a coin with obvious signs of cleaning or find one that may fit in your collection better.

Alternatively if its rare you buy it or keep looking and have a gap its all down to the individual as to what they will tollerate.

If a coin has had something done and there are know obvious signs (so its hard to tell ) then yes it could be classed as conserved or was incidental with regards any damage to the coin.

Some photos or scans may give you reason to not be sure and if in doubt move on to the next ,or return it if your not happy with the coin in hand as the people who read forums and look at coins often will be right.

You mention that toning sometimes becomes so bad that it detracts from the coin this is more the choice of the collector but if your not happy just buy another one rather than mess around trying to change it.The decision to clean or not to clean would i think be better as to buy or not to buy ,if your not sure maybe look for another and dont buy it in the first place.

To say that cleaned coins attract such negative comments on the forum would hopefully mean the individual may learn as i have and continue to ,rather than just thinking every coin is ok.

Sorry if i should of just read your post and not given my thoughts :D

Pete.

 

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As serious question about a serious subject as many coins are traded online where it is very difficult to determine if a coin has been cleaned. Also pointing out the difference on how a museum treats coins against some collectors' opinion. I think I have seen somewhere that services are offered in the US that offer conservation services which I assume include cleaning. As it happens the most common form of  "cleaning" is dipping which has such minimal impact on the coin can it be considered to be cleaning? Also in my original post the decision to clean is not one to be taken lightly.

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I think you have answered your own question regarding the medieval coins they were found filthy and so to conserve them they had to be cleaned. I have no idea what this cleaning consisted of, might have just been a soak in some sort of liquid or it may have been something a little bit more aggressive. However it needed to be done to preserve them also so that people can visit a museum and view them.

in this case it was the right thing to do.

On something not so old such as a 1900 penny there is no need to conserve it. Pete makes a good point "if you are not happy buy another one"

Having said that if I can flick a bit of verdigris off or soak something in acetone I probably will but I judge each coin before doing so and have left many with their natural look even if it is green🤔.

I disagree with your comment about any bright 100 year old coin being cleaned. In some cases they have just been stored correctly with minimal handling and a bit of luck helping preserve their lustre, personally I don't mind a toned coin

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Bit of a coincidence ..........

I received in the post earlier a 1914 UNC penny that looked nice in the scan and although i signed for it at lunchtime have only just had the opportunity to look at it..Unfortunately it has a live verd spot and the Verd has got into the metal.

Rather than think about trying to improve the way it looks i have just put back in the packet and will post it back tomorrow.

For the sake of a couple of £ postage i dont wish to keep it as plenty to choose from and would not sell it someone else other than a dealer .

If a coin has been dipped or anything else that has changed its appearance ,either keep it or return it .The important thing is to be able to tell and then the choice is yours just the same as someone you may sell it to. Some may of just had a light quick dip and some look like they have been painted white 🙂

The one thing i dont like about the TPG Conserved ones you mention is this is no longer put on the label or so i am told ,meaning IMO maybe dealers are submitting them just to inflate the price.

Pete.

Edited by PWA 1967

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I have put a light on the coin to show the spot which did not show properley in the scan and am sure someone will be happy with it ,but not me.

IMG_2406.jpg

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I think the definition of the term "cleaning" is somewhat imprecise. If cleaning is about removing loose surface contaminants without damaging the coin surface in anyway, then it is of course perfectly acceptable and is usually the correct thing to do. This can include removing deposits on dug up coins, or dipping a coin in acetone for example. 

This can be compared to cleaning a valuable oil painting covered with dirt. It is absolutely correct to remove the dirt so that we can actually see the painting below. We want to admire the painting and not the layer of dirt. 

However, conservation is a different thing as this is about altering the actual surface of the object in some way. This can include removing a mount, a mark on a frosted portrait, and yes, in the strict sense removing bad toning or tarnishing. I don't think it is chemically possible to turn a toned object back to its 100% original shiny untoned state.  Whether this removal of toning is obvious / not obvious / exceedingly difficult to detect is another matter. Giving a choice, who wouldn't prefer a coin that has not been "conserved" over a "conserved" specimen. 

Removing dirt off the surface of a painting is cleaning. But chemically turning the pigments that have discoloured with time back to the original colours is conservation. Such conservation is often very acceptable for paintings because each painting is unique and you will not find another better specimen. 

I think IanB is correct in that it is not necessarily true that all bright / untoned coins over 100 years old have been cleaned. There are bronze coins over 100 years old with full lustre but are admittedly rare. By sheer coincidence, coin surface can perhaps be protected from toning by picking up / developing a layer of "substance"? If the layer is thin enough, it will be invisible. 

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This shilling was sealed in the bottom of a Georgian drinking vessel until 10 years ago. No sign of toning here after 250+ years. The same would apply to anything sealed in anaerobic conditions such as hoard coins or any other metal detector find.

138 - Copy.JPG

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Sorry Sword, but I don’t agree with the definitions above,  particularly with “conservation’ which almost never involves removing an original surface, but entails removing foreign matter, contaminants, corrosion products etc to reveal the original surface and possibly with archaeological finds for example treatment  to prevent/ deactivate future or active corrosion eg rust, verdigris, treatment which may be physical, chemical or by environmental control.

The act of repairing damage, a mount mark, piercing, scratch  etc, would be better described as restoration,  in that the actual object is in some way modified to ‘enhance’ it’s appearance, albeit that the intention is usually to return it visually to a previous state.

What we generally refer to as cleaning of coins does usually involve removing something from the original surface, be it by abrasion using polishes (or wire wool or sandpaper for example -shudder-) or by chemically as with silver dip; some might argue the latter only involves removal of corrosion products ie tarnish, but in effect dipping facilitates metal loss by removing a protective coating and exposing environmentally reactive fresh metal which then in turn will tarnish over time.

There is certainly overlap between the above and room for interpretative differences. Personally I do advocate coin conservation where necessary, for example removal of acidic oils and waxes to prevent future corrosion,  or removal of active verdigris to keep the damage localised. And I see so many slabbed coins with dirty, gunged up letters or designs- there is no point placing the coin and the causes of corrosion in the same ‘protected’ environment.

Jerry

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Rob,

We are not talking about coins that have been sealed in some fashion. The coins I was referring to are ones that have been randomly put away in a draw closet etc. and rediscovered later. Your example is not typical for the treatment of most coins however a very nice coin indeed.

Sword,

It is possible to remove tarnish chemically by use of the Al foil bicarb. of soda method that returns the oxide and sulfides of silver back to metallic silver again therefore not removing any of the surface of the coin. As with any cleaning to be approached with caution.

jeldia, 

I think your response to this topic is a good commonsense approach to a serious subject.

In general I think a hoard of coins buried for a thousand years in a porous clay pot would be effected in some way by the environment with all of the conditions for corrosion present in the soil water , corrosive chemicals etc.No plastic sealants in those days.

 

Edited by ozjohn

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8 hours ago, IanB said:

I disagree with your comment about any bright 100 year old coin being cleaned. In some cases they have just been stored correctly with minimal handling and a bit of luck helping preserve their lustre, personally I don't mind a toned coin

Agreed. I bought an UNC set of 1887 JH silver at Warwick which one or two dealers rejected as "cleaned". Well, they weren't - they had a bright 'mirror' finish, which was more pronounced in the fields than the raised designs; cleaned coins tend to show the most mirroring on the highest parts. 

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3 hours ago, jelida said:

Sorry Sword, but I don’t agree with the definitions above,  particularly with “conservation’ which almost never involves removing an original surface, but entails removing foreign matter, contaminants, corrosion products etc to reveal the original surface and possibly with archaeological finds for example treatment  to prevent/ deactivate future or active corrosion eg rust, verdigris, treatment which may be physical, chemical or by environmental control.

The act of repairing damage, a mount mark, piercing, scratch  etc, would be better described as restoration,  in that the actual object is in some way modified to ‘enhance’ it’s appearance, albeit that the intention is usually to return it visually to a previous state.

What we generally refer to as cleaning of coins does usually involve removing something from the original surface, be it by abrasion using polishes (or wire wool or sandpaper for example -shudder-) or by chemically as with silver dip; some might argue the latter only involves removal of corrosion products ie tarnish, but in effect dipping facilitates metal loss by removing a protective coating and exposing environmentally reactive fresh metal which then in turn will tarnish over time.

There is certainly overlap between the above and room for interpretative differences. Personally I do advocate coin conservation where necessary, for example removal of acidic oils and waxes to prevent future corrosion,  or removal of active verdigris to keep the damage localised. And I see so many slabbed coins with dirty, gunged up letters or designs- there is no point placing the coin and the causes of corrosion in the same ‘protected’ environment.

Jerry

Yes, I guess restoration is a more appropriate word than conservation when there is any modification to the metal surface. But we do agree what removing external contaminants without damaging the surface is not consider detrimental to the coin or its value in response to the OP.

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41 minutes ago, ozjohn said:

It is possible to remove tarnish chemically by use of the Al foil bicarb. of soda method that returns the oxide and sulfides of silver back to metallic silver again therefore not removing any of the surface of the coin. As with any cleaning to be approached with caution.

I was indeed thinking of that process. Although the sulfides are converted back to silver atoms, I am inclined to think that some lustre would be /could be lost because the arrangement of the surface atoms might not be as regular as they were previously. I have not tried the process myself and so am only guessing. 

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31 minutes ago, Peckris 2 said:

Agreed. I bought an UNC set of 1887 JH silver at Warwick which one or two dealers rejected as "cleaned". Well, they weren't - they had a bright 'mirror' finish, which was more pronounced in the fields than the raised designs; cleaned coins tend to show the most mirroring on the highest parts. 

I have always liked the highly reflective surfaces on JH coins. Even deeply toned coins can still show this mirror finish. 

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cleaned or uncleaned - which do you prefer?

farthing.jpg

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NGC states that they don’t alter any surfaces during their conversation process, I often wonder what they do though, if joe bloggs dips a coin it’s cleaned, if NGC does the same it’s called conservation 🤷‍♀️

Edited by azda
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There is clearly a conflict of interest when a TPG carries out "conservation" and is then allowed to grade its own handiwork. To be truly impartial, coins after NGC conservation must be graded only at PCGS and vice versa. Obviously, one must not declare that conservation has been carried out and see if the other TPG can work it out for themselves. But this will never happen. 

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14 hours ago, copper123 said:

cleaned or uncleaned - which do you prefer?

farthing.jpg

Cleaned - are you sure? I could get the same effect by using Levels in Photoshop. There's a lot of lint on the 'dull' picture though, which definitely is unsightly.

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16 hours ago, copper123 said:

cleaned or uncleaned - which do you prefer?

Now show us the difficult side... ;)

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On 8/30/2019 at 8:30 AM, Sword said:

I was indeed thinking of that process. Although the sulfides are converted back to silver atoms, I am inclined to think that some lustre would be /could be lost because the arrangement of the surface atoms might not be as regular as they were previously. I have not tried the process myself and so am only guessing. 

Are we taking coin cleaning to a quantum mechanical level? On a serious note I have tried the process and it seems to work well. Before doing this I tried it on some worn coins as well to check the process and get some idea of how long to immerse the coins. I also took a long time to make up my mind to do this. Before and after on an NGC MS 62 encapsulated coin are shown below. I have previously posted these results. Perhaps I could have pushed the cleaning further but in accordance with my extreme caution I minimized the amount of ceaning

NGC MS 62.jpg

 

Florin Ex CGS MS 62 After Clean Take 2.jpg

Edited by ozjohn
Wrong photo

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I agree that dipping a coin with bad or ugly toning is often worth trying. The appearance can be significantly improved making it more marketable and increasing its potential value.

But one of the biggest worry of any form of toning removal is the loss or alteration of lustre. (And lustre is to do with how atoms are arranged on the surface). None of the methods is perfect so that is why there are alternatives. The reason why people are afraid to leave their coin in the liquid for too long is precisely the worry that it might look dull afterwards. Otherwise you can leave it in the liquid for a month until all the even toning is gone.

There are plenty of discussions of cartwheel lustre and flowlines and how these are affected by any method of toning removal including the aluminium method. Goggle and have a look.

I am not saying that toning removal shouldn't be attempted. The numerous discussions on the web has convinced me that once a coin has been significantly toned, none of the methods used will be able to give it the 100% original mint lustre. But I am not arguing that the final result might still be an improvement than the original badly toned state.

Edited by Sword

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With the above example I think the results speak for themselves. As for the original coin and the QM disturbance of the atoms who knows as you will never know what the original was as it has already been destroyed by the toning.. All I can say is if carefully done the effect seems to be minimal. From memory I think the immersion in the Bicarb/ Al foil bath was less than 1/2 a minute with most of the original lustre being preserved. I don't think I could have wished for a better result.

Edited by ozjohn
exra info.

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