To determine the answer to your question all you have to do is first, think a little bit, and then ask yourself a very simple question. The thinking - copper is and always was the most reactive of our coinage metals, until very recent years anyway. And because it is so reactive it tones very, very, easily and quickly. Then consider what the storage methods for coins has been for the past 200 plus years. The question - this being the case, then how is it that there are so very, very many, copper coins that are 50 or more years old, many well over a 100 years old, that are graded and classified as being Red ? There is only 1 reasonable answer to that question
If you are just trying to lighten dark toning it MIGHT be possible. Dilute the dip with distilled water down to 1 or 2% dip so it will react very slowly and keep a close watch on the coin while you are dipping so that you can pull it as soon as the toning lightens and rinse it to stop the reaction. I haven't tried this but I think it might work.
Distilled white vinegar. It is fairly slow to react and you can delute it with distilled water to slow the reaction even more. It is clear so when it gets to the color that is acceptable you can see it, remove it, and rinse it off with water to stop the reaction. Practice on spendable coins first to see how long it takes to get the desired results.
Thanks for all contributions. I just might try the EZest. Would that be preferable to Brasso? What are the active ingredients in Brasso...OK, OK, I'll look...
One of the things I have been neglecting is how reactive the material is from a clean, fresh surface. If aluminum is freed from it's oxide surface coating, it is so reactive as to release hydrogen from water (Drano crystal is sodium hydroxide and aluminum chips, the sodium hydroxide strips the oxide layer from the aluminum and the gas and churning you see is from the aluminum reacting with the water to make hydrogen gas...don't smoke while using Drano...keep away from open flames). Now the copper surface is not as reactive, but still should be protected until it can form a surface protective coating of oxide. Just don't want the oxide to get too dark.
If this is so, why do I remember a picture where Doug dipped half a cent in it and without any touching, the cent got bright?
OK...https://www.conncoll.edu/media/website-media/offices/ehs/envhealthdocs/Brasso_-Polish_-MSDS.pdf Must be the ammonium hydroxide that did the cleaning.
It wasn't Brasso that I used, it was Tarn-X, which is a liquid not a paste. Brasso is a polishing compound that is intended to be used with a rag or cloth. Tarn-x is a liquid that is intended to be used as a dipping solution, there is no rubbing that is needed with Tarn-X as there is with Brasso.
Both are terrible for coins and besides seeming to accelerate oxidization, they leave the coin with a waxy coating. Do not use.
Tarn-X Component CAS NUMBER OSHA Hazard % by Weight 1. Water 7732-18-5 No 85-95 2. Thiourea 62-56-6 Yes 5 - 7 3. Sulfamic Acid 5329-14-6 Yes 3 – 5 4. Disodium Cocoamphodiproprionate 68604-71-7 No <1.0 5. Methanol 67-56-1 Yes <0.05 Similar to EZest
So, if we can eliminate the waxy compounds and do something to slow the oxidation, would we have something worthwhile?
I know this will sound like a horror to many, if not most of you. but when I have a wheat that has both tone and that yucky griss on top of the tone, I just slide it over a soft cotton rag and it lifts the yuck off and leaves the tone. You can actually do it with your thumb too but then your thumb gets yucked and you spread the yuck to the next coins. When I do this I see NO evidence of wear, scratches or any negative repercussions on the coin, even under a loop.
I don't know... I showed my girlfriend this once because she asked. I took two wheat cents and used Tarnx on both. I put one in a sealed zip lock sammich bag and the the other on top of the bag and tossed them on a shelf. After a few days the one out of the bag had not only retarnished, but also had tarnished worse than it was at the outset; a very bright, rusty color and even had some kind of orangy color dust that would wipe off. The one in the bag still looked shiny and waxy. As soon as it was exposed to the air though, it tarnished just as bad and as fast as the other.
LOL I still remember thinking that stuff could make me rich while rubbing it on a 1909VDB when I was 11
It sometimes seem that folklore and stories people made up keep recycling when if you read back through the posts, only a few methods can truly be recommended. I have been using BadThad's verdichem products on copper since they came out, and have never recommended anything else even close to it. It was developed and manufactured by a true research metallurgist chemist, and I have done experiments with many of the products with results here on cointalk. They are higher priced than many as they are made of specific organic chemicals to do the job properly. If you use 99cent store oil in your high performance car, you deserve what you get. Why use catsup, olive oil,dog or alligator dung, taco sauce, vinegar, etc. as you don't know what you are getting. Just follow the directions ( except I use a fine hair artist brush rather than a microfiber cloth) and PCGS nor NGC have detected or commented on the invisible film left. Sniffer doesn't seem to find it. http://www.wizardcoinsupply.com/products/verdi-care.html
No, absolutely not. Brasso and Tarn-X both are about the worst choice there is for use on coins. Brasso because it requires a rubbing by a cloth, which all by itself ruins coins even without the Brasso. And Tarn-X because it is arguably the harshest cleaner there is among all the coin dips.
