How does dipping work

Discussion in 'Coin Chat' started by jcoin126, Aug 25, 2010.

  1. jcoin126

    jcoin126 New Member

    how does dipping work? what does it do to the coin? i hear it strips a very thin piece of the metal to give a fresh look to the coin.
    if done too much, you'll hurt the coin. one dip i hear is market acceptable.
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  3. ddoomm1

    ddoomm1 keep on running

    youve got the guts of it...Ill admit it, dipped a crack out MS-63 1904-O Morgan DMPL and the guy who was helping me said "It looks like it need a bath" so to NGC and with about 1/2 of the toning it used to have ... nothing to be proud of, but once (and quick) not the worst
  4. BR549

    BR549 Junior Member

    A product like MS70 strips off a layer of oxidized metal and must be neutralized with distilled water in order to halt the reaction. Too many dips or to long a time in the solution will dull the mint luster and wash the coin out.

    Acetone will not strip surface metal, but will remove PVC residue and other oils from finger prints, along with other small amounts of dirt and grime.

    Good luck....Happy Collecting
  5. 10gary22

    10gary22 Junior Member

    I am going to add to this query, iof I may. I have a 1932 S 25c that was stored in an old Whitman folder for more than 50 years. Detail is good, but it looks tarnished. What's the best solution to use and how do you do it ? I really don't want to mess this coin up. lol

    I know baking soda and salt will deoxidize silver, but someone said not to use it on coins. I did on some junk silver dimes and they came out OK as far as I can see.

    thanks guys,

  6. statequarterguy

    statequarterguy Love Pucks

    Can you post a pic of the coin? It may not be wise to dip it.
  7. EyeEatWheaties

    EyeEatWheaties Cent Hoarder

    I still wish people would post name brands on here to be on the look out for. whether any seem to have more problems than another are more harsh. Hasn't it been said that these conservation services for hire are often dipping coins?

    I know if I had a conservation business and I was using TarnX to conserve the coins submitted, I wouldn't want anyone to know what I was using. I would be out of business!

    I guess since it is a taboo subject, no one wants to get branded as a dipper. What if I went and got a bunch of different solutions and documented then posted results?

    Furthermore, with all the high tech gadgetry out there, how come no one has posted electron microscope pictures (ok not electron, but some other high powered scope) of the damage that these dips supposedly do with before and after pictures?

    Everyone posts that it damages the coin. I can't see it with my eye or loupe. Someone more knowledgeable that has the evidence of this claim should post the proof. Please?
  8. EyeEatWheaties

    EyeEatWheaties Cent Hoarder

    I swear the deeper I get into this whole subject the more it reeks of a good 'ol boys club designed, managed and protected for their own self serving interests. But then again thats what business is all about! :)
  9. ldhair

    ldhair Clean Supporter

    No. That's not it.
    Very few coins can be helped with a dip and knowing how to spot that coin is not something that can be taught on a forum.
    Dip is an acid and if done wrong, you will kill the coins luster and value. Not something that can be learned in a minute.
  10. Collect89

    Collect89 Coin Collector

    Hello jcoin126,

    I was going to list a few of the previous CoinTalk threads that discussed coin cleaning but the list was very long. You can put the word "clean" into the search field & you will see what I mean. You will find a couple good threads there fully describing the information you are looking for I think.

    I think we have all scrubbed a silver coin with baking soda & water at one time. It makes the coin look bright & shiny to the general observer but most coin collectors take one look at it & they see all the hairlines & a bright coin that no longer looks its age. My recommendation is never use baking soda & water.

    Dips like "jewel Luster" are used to get unattractive toning off of coins. The thing is that what is unattractive to one person may be very attractive to someone else. For this reason I suggest you post a photo of the coins you propose dipping & let some of the other people at CT comment on whether they think it should be dipped. Yes, the dip is an acid & it will take some metal from the coin's surface. A long dip or many dips can destroy a coin's surface. A quick dip can throw away a lot of coin value very quickly and it cannot be undone.

    Prior to dipping, the coin's surface should be free of debris & oils. If it is not clean, then a quick dip may not affect the surface uniformly & you can end up with an ugly splotchy coin that will need another longer dip. It's probably not a good idea to leave that dip residue on the coin as it could do all kinds of nasty things to the coin's appearance with time. I think most people rinse profusely with water.

    When we sign up to the ANA, one of the things we agree to do is preserve the coins in our care for future generations. Take care of your coins & please post some pictures here.
  11. GDJMSP

    GDJMSP Numismatist Moderator

    If you want to know brand names it's pretty easy to find out. Just Google "coin dip". You'll come up with more than you want. And rather than question us, since you are always skeptical, buy some and test them yourself. Then you can see with your own eyes what these chemicals do to coins.

    It's said by many - but nobody knows for sure. All anyone has are assumptions. And to my knowledge there is only 1 conservation service - NCS.

    Yup, you probably would. But that is because TarnX pretty much ruins the coins and anybody with eyes that work can see that. By the same token, since the coins returned by NCS are not ruined, it's pretty safe to assume they are not using TarnX.

    Not so at all. Many of the biggest and most repsected names in the business have no problem admitting that they dip coins. There's no reason for them to object to admitting it or try to keep it secret. Dipping coins is accepted by anyone and everyone in the business, including all of the TPGs.

    And go right ahead and do your own experiments. You'll learn something.

    No need for powerful magnification when you can see it with the naked eye. And literally thousands of pictures have been posted.

    No, not everyone posts that, far from it even. But it's pretty easy for those who are unknowledgeable to make such comments. It's also pretty easy for some to misread or misunderstand what is written. Call it semantics if you wish. The use of a word can have many different meanings depending on who it is that is reading it.

    The word cleaning is an excellent example. Probably more people misunderstand that word than any other. A great many people consider cleaning as being harmful to coins and that cleaning damages coins. But it doesn't.

    The difference is this - harsh or improper cleaning does damage to coins. Cleaning does nothing but remove dirt and/or unwanted contaminants and does not harm or damage the coins.

    But probably 8 out of 10 people will misuse that word.

    Dipping is similar but slightly different. That's because dipping can actually improve the eye appeal of a coin, or dipping can totally destroy the eye appeal of a coin. It all depends on 2 things. 1 - if the dipping is done correctly and 2 - if the right coin is chosen, for not all coins can be improved by dipping.

    As for proof that dipping that can damage coins, I've never even heard of anyone who believed otherwise. That's because the proof is so evident and abundant. Ever see a coin that has MS details (no wear) but yet has no luster ? Well there's your proof.
  12. 10gary22

    10gary22 Junior Member

    Thank you Doug, that really aided my understanding also. I hope to return to this thread at some point and have the guys advise me on a couple of items my local dealer felt would receive higher grades if the tarnish was less. But, newly armed with the knowledge you guys have given me, it's not something that should be done by a newbie, I think. And many of us can't anticipate what is going to happen when and if we do it.

  13. GDJMSP

    GDJMSP Numismatist Moderator

    There is one thing I forgot to mention - the answer to the original question. Dipping works by removing a very thin layer of metal from the coin. Layer is not even the right word, but it expresses the meaning better than most other words. And it does this because coin dips all contain an acid - thiourea. It is this acid that disolves the top molecules of the silver that are toned and washes them away thus revealing the untoned silver underneath.

    You see, toning is not something that sits on top of the metal. Toning is the metal itself that has been altered by a chemical reaction. So the only way to remove toning is to remove the affected metal.
  14. EyeEatWheaties

    EyeEatWheaties Cent Hoarder


    Thank you very very much for breaking down my post with your replies. It was very helpful towards helping me to make a decision on which direction I would like to go with learning more about this subject.

  15. BR549

    BR549 Junior Member

    Pretty bold statement there...btw, I DID GIVE A PRODUCT NAME!


    If your going to make comments like this about every post I will no longer contribute to this forum.
  16. desertgem

    desertgem MODERATOR Senior Errer Collecktor Moderator

    Yes, I know that Science doesn't always know the correct answer, but 2 articles ( can be googled and read, but not copied/quoted) shows 2 possible problems for the use of Thiourea-acid cleaning solutions. Take them for what you think they are worth. Both are from peer qualified specialty journals in metals.

    1. Thiourea bonds more closely to silver than previously though. Casual washing with water doesn't remove the full complex which can (2) later form bonds with sulfur enhancing tarnish, and has caused spotting on silver Daguerreotypes cleaned with it, after a decade or more and IMO, there is no reason it couldn't occur on silver coins so treated as they are not generally covered with wax or polish material like silverware.

    My conclusions would be if one wishes to use it, use it at a diluted solution ( like 1 part EZEST, 9 parts water), and repeat until you have the amount of cleaning you want or you ruin it. The process will be slower, but you are much less likely to overshoot than using the full strength solution.

    Rinse extremely well with water. The article didn't give specific times, as I assume it would differ due to the solution used and the amount of toning/tarnish/corrosion already there. IMO,

  17. GDJMSP

    GDJMSP Numismatist Moderator

    Bit more to it than that Jim since almost all dips contain plenty of other chemicals as well as the thiourea. And you have to worry about them too. But that is why most of those with some experience in dipping coins rinse them in acetone after dipping to neutralize any remaining solution and help wash it away.

    Now some advocate rinsing in distilled water after that and some recommend not using the water at all. I stand in the water camp myself as I've seen acetone leave a whitish cast to the coin too many times.

    But yes, a coin dip will absolutely cause additional changes in time if it is not neutralized afterwards.
  18. Info Sponge

    Info Sponge Junior Member

    That didn't sound right chemically, but I don't want to disagree with Doug unless I've checked my facts carefully.

    Silver "cleaning" solutions are "acidified thiourea", thiourea plus an acid. More information at, though the methods they use for conserving silver artifacts would horrify a coin person.

    The chemistry of thiourea in an acid solution gets rid of silver sulfide, but thiourea with enough acid dissolves silver itself so well that it's a useful leaching agent for extracting silver. So dips remove silver as well as tarnish, just like Doug said.

    Doug's explained many times how luster comes from microscopic flow lines, and if you start dissolving silver the exposed peaks go first, so you get something that would look like normal sorta-flat metal under a microscope, but which at the macroscopic level loses the luster that collectors value highly.
  19. BadThad

    BadThad Calibrated for Lincolns

    I suggest you buy and read the book Coin Chemistry. It will answer your questions and you'll become a more educated collector.
  20. GDJMSP

    GDJMSP Numismatist Moderator

    The leeching of gold is the largest use of thiourea there is.
  21. GDJMSP

    GDJMSP Numismatist Moderator

    Yes, but please don't subscribe to the author's thinking and start ruining coins.
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