syzygy Posted February 8, 2006 Report Share Posted February 8, 2006 Dipping is one of those numismatic terms that I heard used a lot without the kind of operational definition that I like to know. I came to learn that it meant, literally, immersing a coin in some solution that would remove 'bad' tarnish. Yet it does not seem to carry the same stigma that 'cleaning' did. The more collectors and dealers that I talked to, the more I came to believe that it is a common practice. That doesn't make it acceptable, but it should be in the open. In that regard, and for what it's worth, here is some visual documentation on the subject. I used a commercial product that is easily and cheaply available. It contains thiourea (a known carcinogen) and sulfuric acid. I do not suggest that anybody dip their coins. First demonstration was with a silver roosie dime - from change and with some black tarnish. These are the before and after pics for a 5-second dip. Larger Pic Larger Pic The dip almost completely removed the tarnish with none of the abrasive hairlines from other cleaning methods. I would grade this coin as a VF25 and might be a bit suspicious of why it had all that wear with none of the 'dirt', but the dipping is otherwise undetectable (to me) even when using a 5x loupe. But what about an AU/MS coin? That is where dipping is used the most. So, here is a 40% silver Kennedy that I got from a roll search. Larger Pic Larger Pic I'm not sure what you see, but to me, the dipping removed most of the tarnish without removing any of the luster! I see why it is a popular practice. The two coins were pretty expendable and I wanted to try one more experiment with a coin that would be a more likely candidate for dipping. This is a 1964 2 1/2 Gulden from the Netherland Antilles, KM# 7 , .7200 silver, 25 gms (.5787 oz of silver) - for which I paid $12. As you can see, it was not stored in the best of condition and judging by the $3.50 original price, I would speculate that it was in the 2X2 for at least 10-20 years. The obverse has a considerable amount of black tarnish that is not particularly attractive. The reverse is only slightly tarnished. Looks MS to me with plenty of luster still visible. After dipping for a few seconds, the tarnish is largely gone and the luster remains. Ask yourself honestly which coin you would rather buy? I don't like dipping. I especially do not like knowing that I cannot easily tell if a coin has been dipped. Perhaps I should simply assume that after a certain amount of time, a silver coin will either show toning (attractive or not) or it has been dipped. Further, if only a single 'professional' treatment is not damaging, what about the next time and the time after that? After all, dipping is stripping the surface - period. That can't be good and I don't believe that it can be applied with such technical precision as to not cause some stripping to the 'true' surface of the coin. Pessimistically, I fear that many more coins than we generally acknowledge have been dipped. 'Blast white' may often be a synonym for 'dipped'. So that is that. Link to comment Share on other sites More sharing options...
jlueke Posted February 8, 2006 Report Share Posted February 8, 2006 I don't like dipping. I especially do not like knowing that I cannot easily tell if a coin has been dipped. Perhaps I should simply assume that after a certain amount of time, a silver coin will either show toning (attractive or not) or it has been dipped. Further, if only a single 'proffesional' treatment is not damaging, what about the next time and the time after that? After all, dipping is stripping the surface - period. That can't be good and I don't believe that it can be applied with such technical precision as to not cause some stripping to the 'true' surface of the coin. Pessimistically, I fear that many more coins than we generally acknowledge have been dipped. 'Blast white' may often be a synonym for 'dipped'. So that is that. You should get that Coin Chemistry book Toning=Corrosoion which just means that some of the coins surface has reacted to for a corrosive compound. Dipping does not undo this process, it basically removes part of the coins surface. Mostly the toned/corroded area but also a bit of the rest of the coin. Thus the longer the total exposure to the dipping solution the more impact on the natural luster. Many raw Morgans have been dipped to the point of having no natural luster. Coins that are left in the open air, in paper envelopes, wood cabinets, cardboard, or many other storage cointainers will tone. But, if coins are protected from the environment, and sulfur compouds they can remain blast white naturally. Link to comment Share on other sites More sharing options...
GDJMSP Posted February 8, 2006 Report Share Posted February 8, 2006 But, if coins are protected from the environment, and sulfur compouds they can remain blast white naturally. I agree, but just how did they do that 100 - 150 yrs ago before modern coin holders existed ? I believe that syzygy is 100% correct when he says - Perhaps I should simply assume that after a certain amount of time, a silver coin will either show toning (attractive or not) or it has been dipped. .......... Pessimistically, I fear that many more coins than we generally acknowledge have been dipped. 'Blast white' may often be a synonym for 'dipped'. Link to comment Share on other sites More sharing options...
Art Posted February 8, 2006 Report Share Posted February 8, 2006 A nice experiment. Thank you for sharing this information with us. From your pictures it's not obvious to me that the coins have been dipped. The Netherlands coin is significantly improved and would certainly be a more attractive buy after the treatment. I've seen pictures of coins from NCS in their before and after state and some are even more radical a change than what you have shown. I'm not sure their process is the same as yours, but I'd bet it's pretty close. Link to comment Share on other sites More sharing options...
Guest Stujoe Posted February 8, 2006 Report Share Posted February 8, 2006 Good pics and experiment. To me... The first one show why you should not dip circulated coins, the second shows that dipping is not a cure all and the third shows why some people do dip coins. Did you use any solution to completely remove and neutralize the dip? I once bought a Kennedy that was nice and white but within a month it developed ugly brownish toned spotches all over it. I am about 99% positive it was dipped and not rinsed Link to comment Share on other sites More sharing options...
syzygy Posted February 8, 2006 Author Report Share Posted February 8, 2006 Did you use any solution to completely remove and neutralize the dip? I once bought a Kennedy that was nice and white but within a month it developed ugly brownish toned spotches all over it. I am about 99% positive it was dipped and not rinsed All three were put under running water for about 10 minutes, but only the 2 1/2 G was rinsed further with distilled water. I certainly will report if there are some dramatic color changes later as I plan on keeping the coins. Link to comment Share on other sites More sharing options...
ageka Posted February 8, 2006 Report Share Posted February 8, 2006 I got intrested by all these discusions so I just ordered the second edition of the introduction to coin preservation Of course it is in German and of course being an introduction only it is only 200 pages German being my fourth language and the book probably being full of chemical redox raction it will take me like 3 month to understand http://www.lindner-falzlos.de/eshop2/index...roducts_id=4306 Link to comment Share on other sites More sharing options...
jlueke Posted February 8, 2006 Report Share Posted February 8, 2006 I agree, but just how did they do that 100 - 150 yrs ago before modern coin holders existed ? In Coin Chemistry the author did a test in his kitchen. He put some silver spoons on the wall and two in tin containers that were common in the 1800's. Sure enough the protected coins did stay brilliant. While most storage methods from the 1800's would probably lead to toning, it was possible to prevent it. That doesn't prove that most coins haven't been dipped, it just shows that a white coin MAY not have been dipped. Link to comment Share on other sites More sharing options...
jlueke Posted February 8, 2006 Report Share Posted February 8, 2006 I got intrested by all these discusions so I just ordered the second edition of the introduction to coin preservation Of course it is in German and of course being an introduction only it is only 200 pages German being my fourth language and the book probably being full of chemical redox raction it will take me like 3 month to understand http://www.lindner-falzlos.de/eshop2/index...roducts_id=4306 Well that's cheap, I should get one. It is my first language Link to comment Share on other sites More sharing options...
AuldFartte Posted February 8, 2006 Report Share Posted February 8, 2006 Great experiment!!! I have dipped a couple of coins to remove really ugly tarnish. So ugly that nobody would call it "toning", and it works pretty well for a ONE TIME application. I found, on a cheap MS Canadian silver dollar, that the second dip in JeweLustre will begin to affect the lustre. Over-dipped coins appear "washed out" in hand - as if the natural mint lustre just isn't there. The penchant for some dealers to dip AU and MS coins, usually resulting in asking prices higher than actually warranted, compels me to search out naturally toned coins, especially larger sized silver. Link to comment Share on other sites More sharing options...
ageka Posted February 8, 2006 Report Share Posted February 8, 2006 Well that's cheap, I should get one. It is my first language I ordered it from Lindner themselves since there is a dozen copies of edition one for sale on ebay announced as new Which they are but outdated and they only want like 3 euro for the edition one copies So I decided I would rather pay the extra 7 euro for a second edition and not to take any chances I ordered it from Lindner Link to comment Share on other sites More sharing options...
Dan769 Posted February 9, 2006 Report Share Posted February 9, 2006 Well done syzygy, I have a couple Mint state CC morgans that have started to get blotchy , milky spots on them , just like Stu's example, which leads me to believe they were dipped and improperly rinsed. I almost want to sell em and "upgrade" my set by getting the same date in XF-AU. Link to comment Share on other sites More sharing options...
bobbycoin Posted February 9, 2006 Report Share Posted February 9, 2006 syzygy, Wow! Great information! Great Pics! Big thanks! -Bobby Link to comment Share on other sites More sharing options...
stu62 Posted February 9, 2006 Report Share Posted February 9, 2006 One of the most informative threads ever.Well done! Link to comment Share on other sites More sharing options...
Burks Posted February 9, 2006 Report Share Posted February 9, 2006 Interesting thread. Looks like I'll have to start reading about this more. Have some nasty coins I'd like cleaned up a bit. Link to comment Share on other sites More sharing options...
Guest Stujoe Posted February 9, 2006 Report Share Posted February 9, 2006 All three were put under running water for about 10 minutes, but only the 2 1/2 G was rinsed further with distilled water. I certainly will report if there are some dramatic color changes later as I plan on keeping the coins. <{POST_SNAPBACK}> This is not the Kennedy I was talking about but here is a Washer I have that I suspect had something done to it. It sure turned bad after I had it for a while ... Link to comment Share on other sites More sharing options...
jlueke Posted February 9, 2006 Report Share Posted February 9, 2006 I just got some cleaner and some Dells darkener. So I'll try an experiment or two in the next few days. Link to comment Share on other sites More sharing options...
AuldFartte Posted February 9, 2006 Report Share Posted February 9, 2006 This is not the Kennedy I was talking about but here is a Washer I have that I suspect had something done to it. It sure turned bad after I had it for a while ... Yeah, that splotchy toning can be a sign of a dipped-and-not-rinsed-and-dried-properly coin Link to comment Share on other sites More sharing options...
GDJMSP Posted February 10, 2006 Report Share Posted February 10, 2006 In Coin Chemistry the author did a test in his kitchen. He put some silver spoons on the wall and two in tin containers that were common in the 1800's. Sure enough the protected coins did stay brilliant. While most storage methods from the 1800's would probably lead to toning, it was possible to prevent it. That doesn't prove that most coins haven't been dipped, it just shows that a white coin MAY not have been dipped. I agree it's possible. But is it probable - that's the real question. Kinda curious though, did the author mention how long he kept those spoons in the tin containers ? The answer doesn't really matter, I'm just curious. What matters to me is this - say an owner kept his coins in a tin container and it did prevent them from toning. What about the next owner or the next ? With a coin that's 150 yrs old, it is likely that at least 6 and possibly even 40 or 50 different people owned that same coin during the course of 150 yrs. To think that all of them kept this coin in some type of container that prevented toning just isn't realistic or very probable. Do you see what I mean ? So an experiment such as you describe in the book is pretty much meaningless. It only shows what was possible to happen for a fraction of the coin's life. My purpose is not to be argumentative, I only intend to stimulate thought and common sense. In my opinion too many authors, so called experts, conduct experiments and such and then form conclusions that are based on assumption instead of facts. It's always possible for anything to have happened. But if the probability of those events occurring is slim to none then what do have ? Not much I think. Just like it's possible that an asteroid will strike the earth tomorrow and wipe out all life - I really aint too worried about it actually happening. Link to comment Share on other sites More sharing options...
jlueke Posted February 10, 2006 Report Share Posted February 10, 2006 The silver spoon experiment was done over a year. I agree that this doesn't prove anything about any given coin. It just means you cannot assume anything. Some coins will be completely natural, most white ones have probably been dipped at least once. I wouldn't say the probability is slim to none though. Morgans sat in bank vaults into the mid 1960's. The coins buried inside bags were probably prety well protected by their neighbors. Since coin collecting was quite popular by then it's not that unreasonable to find fully original Morgans. Bust halves are another matter Link to comment Share on other sites More sharing options...
jlueke Posted February 10, 2006 Report Share Posted February 10, 2006 Here's a case where dipping worked quite nicely. It;s my specific gravity calibration coin, a 2002 Silver Eagle. The dip used was e Z est Coin Cleaner. Before: After: Link to comment Share on other sites More sharing options...
Sir Sisu Posted February 10, 2006 Report Share Posted February 10, 2006 It;s my specific gravity calibration coin, a 2002 Silver Eagle. ... Is there a thread somewhere that explains how that works? I have a coin that according to Krause, has two varieties for the same year- same size and weight, but different silver content: 0.500 and 0.900. I do not know which mine is. Link to comment Share on other sites More sharing options...
jlueke Posted February 10, 2006 Report Share Posted February 10, 2006 If it's a modern coin, you should be able to tell by weight? Or is it not listed like that? Specific gravity is just weight in air / weight in water. .900 coin silver will give you a 10.3 +- .1 if you are doing it at home. .500 will be considerably less. Link to comment Share on other sites More sharing options...
jlueke Posted February 10, 2006 Report Share Posted February 10, 2006 Here's one where the e Z est Coin cleaner did little, the Nic a lene coin cleaner seemed to work a bit better. Before e z Est: nic a lene Link to comment Share on other sites More sharing options...
Sir Sisu Posted February 10, 2006 Report Share Posted February 10, 2006 If it's a modern coin, you should be able to tell by weight? Or is it not listed like that? Specific gravity is just weight in air / weight in water. .900 coin silver will give you a 10.3 +- .1 if you are doing it at home. .500 will be considerably less. Both are listed at 25g. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.