Dipping MS and Proof coins

That is the second best reply I have received in any thread! Thanks, I love it. BTW, I'm still learning, have an open mind, and cannot wait for others to try some experiments wit dip and report their results.

 

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Experimentally proven to be Not True.

 

Dipping has some risk factors. I don,t dip coppers because it usually leaves a pinkish tone on M S coins. I have dipped many proof coppers with mostly good luck, however sometimes there is a bad reaction. I dilute the solution and have better luck. Modern zinc coppers don,t like to be dipped. Silver coins react well without too many problems. Proof silver is the easiest to restore. Many older silver proofs have environmental issues due to improper mint packaging. Brown Ikes are a great example of bad packaging. I always dip the Brown Ikes and 70,s red case proof sets. These plastic cases are "ticking time bombs" and most coins in these cases are or will be ruined if left in them! I have about a 90% success rate dipping these.

I use a solution of half clear ammonia and half distilled water. Use tongs or medical gloves, only touch the edges, dip the coin several times [swish it in the solution], rinse in hot running water [repeat if necessary], rinse again in distilled water,[tap water is very polluted] dry with a hair dryer[never use cloth and never touch the surface with anything]. Experiment with ugly Ikes. I would submit more valuable coins for professional restoration.

Chascat

 

I, as a rule, do not dip coins. I have experimented with very cheap coins in the past. However, my hard and fast rule is not to dip. The reason for this is that there is a very fine line between dipping and overdipping, whereby the coin is ruined, the luster lost, and metal is actually removed to a significant degree. If I wanted a coin that had absolutely clean surfaces, and I often do, it is far easier too buy it that way. What is the point of buying a coin or owning a coin where the eye appeal is not to one's liking? I do realize the necessity for dipping and conservation, especially if the toning on a valued coin has gotten out of control to the point of devaluing the coin. However, I do not choose to do any dipping myself for one simple reason--I am not very good at it. If I owned a key date as an example, and it had some unattractive surfaces that needed to be delicately removed, I would pay for conservation services. Otherwise, I tend to buy only what I like, in terms of eye appeal.

 

This poster knows what he is doing...good advice.

 

More good advice! keep it coming...

 

By any chemical definition I know of, thiourea is NOT acid. Thiourea is commonly used in an acidic solution though.

 

Have to get a chuckle from this one. One of the labs I teach asks the students to rank elements they are examining as dull or lustrous. I am often asked just what luster is, and I respond that it means if it is shiny or not. Since we are in a forum with specific definitions for terms, luster to a coin collector obviously means numismatic luster, however we do enjoy beating each other over the heads with the club of definitions.

 

Like this post. Cleaning (or conserving, if cleaning offends your sensibilities) by many means should be acceptable, except that the clean, stripped surface that is left is very vulnerable and it is a hard job to protect it.

 

Neat, so it is a catalyst. Thanks. I never cared what dip was, just what it did

 

Sorry, not a catalyst either, just one of the ingredients that go to making up the witch's brew that constitutes a reaction.

 

Some dippers use a final rinse of alcohol, they say it helps seal the surface and dries much quicker with the hair dryer. I have not tried method because I,ve seen ghost spots on some of the coins. Dipping generally does not remove milk spots, carbon spots, or rust stains on the early 50,s proofs.

As with all proofs, an air-tight holder is the best storage method. They are much less vulnerable to environmental hazing.

 

Thought it helps the reaction take place...perhaps a pseudo-catalyst?

 

No more a catalyst than eggs are in making a cake. The thiourea is a reactant that causes the silver oxide or silver sulfide to revert to silver and H2S or H2O. Perhaps you have noticed the "rotten egg" smell when dipping silver coins.

 

Insider. Are you saying that dip is not an acid? Dip will remove luster. Are you possibly thinking of giving a coin a bath in acetone?

 

No. Many dips are acids. Some chemical "dips" are not...Ivory soap. After a while (depends on a multitude of variables), when improperly used, when used on the wrong coin etc, etc both acidic and basic dips will eventually destroy luster as they EAT AWAY some coinage metals.

A chemist just put an end to the myth that thiourea is an acid.

Now, ask the chemist your questions as I don't claim to be one

 

I use alcohol on nickel coins after conservation. A dip should remove many spots or stains (even on Proofs) if the coin is PREPARED first. Forget about "milk stains." We always said that the person who learns to remove "milk stains" from silver or "carbon spots" from cents will become filthy rich! That is all I care to say

Perhaps the expert conservators who accused me of helping people ruin their coins can come up with some useful tips during the 2 seconds you have to work.

Good advice. The fresh surface of a coin is vulnerable. Even an air-tight holder will not prevent color changes if the coin was not neutralized completely . Does it ever end?

 

Tried a sonic cleaner on an old coin. It did a fine cleaning---and exposed some large scratches.

 

Be careful!

 

BIG PROBLEM HERE WILL RE ENTER REPLY: See post#157