Extreme copper cleaning

Don't read it then. Don't troll. I was searching for information on taking care of copper and this showed up in the deep resources of the website. Make a positive contribution to the subject, or move on to something more interesting to YOU.

 

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Ok I didn't know that happened don't be so extra and I don't call that trolling at allgoodbye.

 

So here is my question. I have several Israel Purtah which are in wonderful shape since 1954, BUT then have some brown marks on them, similar to thumbprints, ANd I was condiering conservation methods.

 

Shoot it out of the air with a gun, like in the old west, as suggested in this 12 yr old thread. And use an Uzi to stay in the theme of your coin.

 

Read post #18 again.

 

Nobody said that.

 

Copper/bronze coins don't like being messed with. The color of the surfaces are going to change and they probably won't look natural.
I don't know of a way to remove old finger prints. The toning is deep in the surface. The services can reduce the looks of a print or spot but most of the time they will still be there.

 

The easiest and cheapest way to clean copper and brasses is by doing what metal workers do to clean and remove flux from it. They use a pickle solution sodium bisulfate Better known as Pool pH reducer.
Sodium bisulfate is used primarily to lower pH. it also is used in metal finishing, cleaning products, and to lower the pH of water for effective chlorination in swimming pools and hot tubs.
It works best at about 180ºF DO NOT HEAT TO BOILING BECAUSE DANGEROUS FUMES ARE RELEASED. Hot tap water will work, you will be able to see the change in a short time depending on the type of deposits.
Use only glass or plastic containers to hold and clean the items. Any steel in the pickle will cause an electrical charge and flash copper plate any items in it.
Neutralize the pickle by adding baking soda, it will froth up work in a sink or dish pan when it slows down it is same to flush down the pipes.
If you don't have a pool or spa a small bottle will last a long time it is a powder mix with water to the needed strength to use.

 

I did a similar experiment two weeks ago with 13 different methods to clean Norwegian wartime iron coins. I haven't taken the time yet to post the results, but I can assure you that none were as drastic as these four were on the copper coins.

Steve

 

I realize you probably meant to type Prutah, and you mentioned the coin condition in 1954, but that does not mean you meant "modern" Prutah, as opposed to "ancient" Prutah. I mention this, because the copper composition is not the same, and any conservation methods have to be considered for the difference of composition, I think.

 

I don't know about this, but I do know that this method has caused issues with EAC and 19th and 20th century coins.

 

These are the coins I am looking to improve

 

I vote leave them alone.

 

Sound good, but I don't have a work space that can accomidate this. Toxic fumes will not just kill me, but the 30 others that live on this floor.

 

https://en.wikipedia.org/wiki/Sodium_bisulfate