Question about cleaning with E-Zest

First, let me state that I don't clean any coins of value so I don't need a lecture about cleaning coins. However, when it comes to common coins that I have in series sets of modern coins, I do clean them if they are so dirty that they are eyesores. For example, in my state quarters collection I have a few states where the coins were too dirty and looked out of place next to all the other brilliant ones. Since they are only worth face value (and won't be worth any more than that in my lifetime), I cleaned about a half dozen of them using E-Zest and then rinsed them with distilled water. Right after cleaning, they all looked great. But the next day two of the six turned an ugly brownish color. The other four still look great. I must have done something wrong using E-Zest but I can't figure out for the life of me what it was since all the coins were the same (Clad State quarters) and I cleaned them all the same way, yet 2 of them got ruined. (I should say that I recleaned the 2 and they look much better now, but still some brown on them). Has anyone ever used E-Zest for cleaning and seen this? Any idea what might be causing this (did I dip it too long, too short, should I not use distilled water to rinse?). I just don't get why 4 cleaned perfectly but 2 got ruined. Thanks for any help/suggestions.

 

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Dip in Ezest, then dip in a base solution like baking soda or ammonia then rinse with distilled water. The base will neutralize the acid that's in E-Zest. There's a few chemists on this board that might be able to help too.

 

I've also used it on some non-valuable coins and haven't had this problem.

 

E-Zest is formulated primarily for removal of silver salts (e.g. silver sulfide the usual, main cause of toning) from the surface of metallic silver. Use on other metals may produce unpredictable and undesirable results.

Cal

 

The coins turned brown (called Dip Staining) because they were not rinsed sufficiently. Also, when you dip a clad coin it leaves the copper edge too pink and out of the normal. I have heard that NCS knows how to avoid this.

 

Insider got it, Incomplete rinsing. You have to rinse and rinse and rinse to make sure you get rid of EVERY trace of the dip. This is also why rinses should be a FLOWING rinse to carry away the traces. If you just rinse in a bowl of water there will still be diluted traces of the dip on the coin when you take it out and dry it. (Because your rinse water is contaminated. And the more coins you dip the more contaminated it becomes.)

 

Were your coins dirty or toned? E-Zest is only appropriate for one of those two. It isn't a "cleaner." It's a chemical stripper which removes metal from the surface of a coin. Scares the heck out of me to think someone's using thiourea on dirty coins; I'm guessing you're just using the term to refer to toning.

Another consideration is, after the dip you end up with a coin whose surfaces are stripped completely clean, and will therefore be more susceptible to retoning in the future. I learned that one the hard way.

 

I have never trusted just water to neutralize a dip. Am I wrong?

 

The trick Is fast moving, running luke-warm water from a faucet. I've never experienced dip residue issues and always hold the coin under a fast faucet. One side for a second then the other side then flip back and forth for a few more seconds and boom. I also put the coin vertical under the water too yobpush any dip out of the reeds then move my finger and thumb to a different part of the reeds and rinse where they were. Just be thorough. That's the key

 

Yes. Usually baking soda is the next step after a dip. Then the baking soda needs to be neutralized! "Properly used" ultrasonic treatment is the best. Heat speeds reactions.

 

An ultrasonic cleaner won't neutralize anything; it's mechanical, not chemical. It simply provides a more thorough rinse in the sense of having the rinse water penetrate into nooks or crannies. However, most ultrasonic cleaning machines are designed for batch use rather than flow-through use. So anything they remove from the coin is still in contact with the coin, but is extensively diluted. There is still a need for rinsing under flowing water, preferably distilled or de-ionized water.

Be cautious about putting an ancient coin in an ultrasonic cleaning machine. Many are internally fragile and may break.

Cal

 

I always used the baking soda to neutralize the dip and water to wash off any soda that was left. Never knew I needed to neutralize the soda.

 

Thanks for the additional instruction and comments: @calcol said: "An ultrasonic cleaner won't neutralize anything; it's mechanical, not chemical. You think? It simply provides a more thorough rinse in the sense of having the rinse water penetrate into nooks or crannies."

THAT'S WHY WE USE THEM! Note: Conservation involves many steps. Anyone wishing for a detailed description of the process should take a course. It is too much trouble to post COMMEN SENSE things like "make sure your chemicals are fresh and not contaminated." I'll leave that up to others here.

@calcol said: "There is still a need for rinsing under flowing water, preferably distilled or de-ionized water." I saw that in use at NCS: FLOWING de-ionized water.

Warning: Anything I post is my personal opinion and is not intended to be of any instructional use. Play with your coins at your own risk but I don't advise it. Even knowledgeable professionals ruin coins that don't belong to them!

 

Warning: everything insider posts is usually a mountain that was once a molehill

 

Depending on the fragility of the coin, I place it in the sink (on a wash cloth if you prefer) and run tap water over it (hot, then warm, then cool) for a few minutes. If the coin is a real goodie, you could then use distilled water, if not, just pat or blot it dry.

 

Wow, guys, what a treasure trove of practical information. I give you all a Like.

 

As for the running faucet.........what if I live in Flint (MI)?

 

Then I'd sue the government for health problems and investment losses!

 

Local or Federal?