Friendly Metal Detecting Forums   Metal Detectors
List all sponsors

Go Back   Friendly Metal Detecting Forums > Everything About Finds > Cleaning Your Finds

Reply
  
Thread Tools Display Modes
  #1  
Old 02-01-2018, 12:15 PM
Fool Fool is offline
Senior Member
 
Join Date: Jan 2018
Location: Western NY
Posts: 299
Default cleaning off sulfur residue

Sadly my mother passed away 2 years ago, i moved most of the stuff out of the house into mine due to high sulfur in the air from the well water. I finally got around to going through the coin collection and a lot of the coins are black from sulfer, mostly wheat pennies. Is there a good, safe way to clean them? I doubt any are worth a lot I just want to clean them up so they don’t get worse…
Reply With Quote


  #2  
Old 02-04-2018, 02:07 AM
coin chaser's Avatar
coin chaser coin chaser is offline
Elite Member
 
Join Date: Mar 2012
Location: illinois,chicago suburbs
Posts: 2,801
Default

Sorry to hear about your mother. Unfortunately I don’t think you can harm them any cleaning them because sulfur eats copper pretty bad. If they are black I would be willing to bet that the copper is pitted as well.
Reply With Quote


  #3  
Old 02-04-2018, 12:18 PM
ArthurEvans's Avatar
ArthurEvans ArthurEvans is offline
Senior Member
 
Join Date: Mar 2016
Location: Hyde Park, Dutchess County, NY
Posts: 276
Default

I've used this on silver. Seems like it ought to work on copper, but haven't tried it myself.

http://scifun.chem.wisc.edu/HomeExpts/tarnish.html

__________________
Hyde Park, Dutchess County, NY; Central CT
Tesoro Tejón, White's M6, Garrett AT Pro and Pro-Pointer

Reply With Quote


  #4  
Old 02-05-2018, 10:06 AM
Fool Fool is offline
Senior Member
 
Join Date: Jan 2018
Location: Western NY
Posts: 299
Default

Originally Posted by ArthurEvans View post
I've used this on silver. Seems like it ought to work on copper, but haven't tried it myself.

http://scifun.chem.wisc.edu/HomeExpts/tarnish.html
It may work but the chemical reaction will be different...


3 Ag2S + 2 Al --/> 6 Ag + Al2S3
silver
sulfide aluminum silver aluminum
sulfide

It will actually be :

CuS + Al --/> Cu + Al2S3
Since it is an electrochemical reaction it should work since Copper is a good conductor. I guess only one way to find out.
Reply With Quote


  #5  
Old 02-06-2018, 12:35 PM
ArthurEvans's Avatar
ArthurEvans ArthurEvans is offline
Senior Member
 
Join Date: Mar 2016
Location: Hyde Park, Dutchess County, NY
Posts: 276
Default

It does seem like it ought to work, but it doesn't. I've just done a trial, overnight, with tarnished pennies, following the silver method above. I think the difference is that silver has a much higher reduction potential than copper... Also, although copper does have a high affinity for sulfur (that's why they use it so much in liquor stills, it takes out sulfur and cleans up the flavor), most of the tarnish/patina on copper is probably copper (II) oxide.

I've got some other ideas, though, that I'm going to test out. One I've done before is heating the copper in hydrogen gas, but that's not practical unless you're in a lab! So I'm going to see if I can find some less explode-y methods that might help.... I'll post here if I come up with anything that can be reasonably done at home.

__________________
Hyde Park, Dutchess County, NY; Central CT
Tesoro Tejón, White's M6, Garrett AT Pro and Pro-Pointer

Reply With Quote


  #6  
Old 02-06-2018, 10:27 PM
ArthurEvans's Avatar
ArthurEvans ArthurEvans is offline
Senior Member
 
Join Date: Mar 2016
Location: Hyde Park, Dutchess County, NY
Posts: 276
Default

I've run another experiment on this and had good results... but I think I'll start a new thread. Cleaning copper.

__________________
Hyde Park, Dutchess County, NY; Central CT
Tesoro Tejón, White's M6, Garrett AT Pro and Pro-Pointer

Reply With Quote


  #7  
Old 04-25-2018, 12:01 AM
AirmetTango's Avatar
AirmetTango AirmetTango is online now
Supporter
 
Join Date: Apr 2017
Location: NW Ohio
Posts: 721
Default

Originally Posted by ArthurEvans View post
I've used this on silver. Seems like it ought to work on copper, but haven't tried it myself.

http://scifun.chem.wisc.edu/HomeExpts/tarnish.html
Thanks for posting this. I just tried the method outlined in the link on a Merc that was in pretty rough shape - more oxidation than any other silver that I’ve dug. I needed to reheat the solution several times as the directions suggested, but overall, the results were pretty good! Much of the black oxidation is gone!

Some before and after pics are below:
Attached Images
    

__________________

Oldest coin: 1853 Braided Hair Large Cent (Honorable Mention: 1857 Flying Eagle Cent)
Oldest silver: 1861 Seated Liberty Dime
Oldest foreign coin: 1939 Mexican 2 Centavos
Reply With Quote


  #8  
Old 05-28-2018, 04:06 PM
AirmetTango's Avatar
AirmetTango AirmetTango is online now
Supporter
 
Join Date: Apr 2017
Location: NW Ohio
Posts: 721
Default

Adding additional pics of the same cleaned Merc dime with better lighting:
Attached Images
  

__________________

Oldest coin: 1853 Braided Hair Large Cent (Honorable Mention: 1857 Flying Eagle Cent)
Oldest silver: 1861 Seated Liberty Dime
Oldest foreign coin: 1939 Mexican 2 Centavos
Reply With Quote


Reply


Thread Tools
Display Modes

Forum Jump


All times are GMT -4. The time now is 12:57 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.