Cleaning cupronickel coins 1930's French Francs

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So Kato found some French coins and may be interested in cleaning them.
Apparently they are cupronickel 75/25 mix.

What would be a good safe method of clean these coins please?

Gh
 
If it's the coins in the other thread, they have little value based on the condition, so why not take this opportunity yourself to try a few different ways, and let us know how you got on? CAB one, LJ another, Armorall Cleaner soak etc....

0.02c
GGA
 
I think citric may stain them copper pink, I'd try just wet the coin and rub between your fingers with dry bi-carb til you get them to where you want
Moist not too wet so it's a fine abrasive, if there too far gone polish with metal polish :cool:
 
Soak in Vaseline for 3 days...then .scratch the dirt of working the raised parts of the coin with wooden skewers...or toothpicks...then clean with tooth brush...rinse and repeat process...until desired finish...rub again with vaso..pat dry with paper towl... :Y:
 
GypsyGoldAu said:
If it's the coins in the other thread, they have little value based on the condition, so why not take this opportunity yourself to try a few different ways, and let us know how you got on? CAB one, LJ another, Armorall Cleaner soak etc....

0.02c
GGA

Did CAB on modern Aus coins and yes they did come out a little copperish, I guess we need to avoid acids that like Nickel.
But yes we could try a number of methods.
 
My advice would be to start with the 'heavier' methods followed by each stage as less & less severe....bit like painting a car or wall etc,.. the final finish will only be as good (reflective polish state) as the way you layer each level of abrasion from heavy to light. :cool:

eg, perhaps use the bi-carb rub 1st, followed by a dunking, and finally if desired, a polish of firstly with Brasso, and finally with some Silvo

I wouldn't advise ANY of the above if you had recovered a 'collector's item' though.... ;)

As to the 'dull' copper coat, swift abrasion with a scotch pad can brighten that up....that will be the copper content 'leeching' out of the broken down surface of the coin...perhaps a longer soak will remove the 'oxidized' leeching and follow with a clean up???

Nickel does tend to look 'pinkish'...yet when side by side with chrome, it looks to be more 'yellow'...whereas 'cobalt' will look more 'blue' :Y:
 
When I did the CAB I used CA in the rotary tumbler, maybe I will just use a bit of detergent and water to allow them to clean with just the stainless pins,
will try one coin first.
I will try one in a vibratory tumbler also with a bit of Nufinish polish in the corn cob media.

ONLY because they have LOW value

I think electrolysis would be damaging unless I pulled Nickle over onto them.
Maybe some other light chemicals for the crud that doesnt attack copper or nickle ?

I think when I had a copperish look to modern coins there were brass cases in there too.

Here are some coins with just CT18 in the water with the pins, done in the rotary tumbler.
After I decontaminated the Tumbler with CT18.

The 1c on the left was VERY toasted with corrosion and hardly recognisable, it is actually shiny and the dirt is shadows in the pitting.

1487808770_img_0367.jpg


1487808770_img_0368.jpg
 
I've not had experience with tumblers, but your results look good.

Revisit my post above as i edited some extra info. in.

Furthermore...if you are 'attracting' copper from your 'cathode'....try reversing the polarity. Make sure you change your 'solution' for a fresh sample though, and if using a copper cathode, remove and 'activate' by rubbing the surface with a scotch-brite pad (not 'steel wool' due to contamination) till it goes from brown to a clean finish, this will speed up the process.
 
GypsyGoldAu said:
I've not had experience with tumblers, but your results look good.

Revisit my post above as i edited some extra info. in.

Furthermore...if you are 'attracting' copper from your 'cathode'....try reversing the polarity. Make sure you change your 'solution' for a fresh sample though, and if using a copper cathode, remove and 'activate' by rubbing the surface with a scotch-brite pad till it goes from brown to a clean finish, this will speed up the process.

Okay so If I want to try to clean via electrolysis, I would use nickel as a cathode ? and a cupronickel anode ?
That would reduce the attraction of the copper out of the alloy? Possibly depositing a layer on nickel onto the coin?
 
I would use that as a 'finish' process after cleaning,..but yeah, your on the right track. If you have some nickel around it's a better way to go, though you can't undo the 'leeching' that has already occurred, so best to draw as much out now as possible, before trying to seal-coat it with nickel...imo.

I just used 'copper' as the cathode example, as i wasn't sure what you had used, but many do just use copper in a homemade bench system.

You will have to determine if your set-up is 'cleaning' the coin, or 'attracting' the copper from the cathode first. As i said, a switch in polarity will reveal which is occurring. Remember the (+)Positive electrons (Anode) are 'attracted' to the (-)Negative (Cathode) so goes the 'flow' of your suspended solution. Also rinse the anode & cathodes when changing polarity/solution/cathode to minimize contamination.

Hope that makes sense..i'm an operator and not a teacher lol... ]:D
 

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