Question on cleaning older copper...

[Erik in NJ]

They used to say, put them in Extra Virgin Olive Oil, but I think I read here that this is not the recommended way. Did I read something about warm peroxide or something being the way to go? Please enlighten me. I have an IH and a LC that I don't want to blow the date off of - the ground has not been good to them and both are quite corroded - I can just about make out a date on each of them - Bob NH's Canadian LC cleaned up real nice - so what's the secret on cleaning these coins in the most gentle fashion? Thanks, Erik

 

[Chris(SoCenWI)]

Erik,

Partially fill a shallow dish with hydrogen peroxide and put it in the microwave- without coins- and nuke until boiling, then drop the coins in and wait until it stops fizzing. Take the coins out and gently clean with terry cloth. Repeat if there is still dirt left.

This treatment will lift the dirt off but not the patina. I've had many copper coins clean up beautifully with this method. I originally used olive oil but with much worse results. Perhaps if you let the coins soak in it for a couple of years....

If they are real corroded, have the blue/green gunkies, or are falling apart peroxide will not save them. Nothing will that I know of will. But peroxide will most likely not damage them further, while many other cleaning methods might.

Chris

I'm going to order a voltage and current regulated power supply and experiment with electrolysis. Think I can control better than with a jerry-rigged wall wort. Will post results.

 

[Erik in NJ]

Thanks for the info Chris - I think it was your post that I originally saw - some good advice there. I'll try it out this evening and report back here. Let me know how he electrolysis works out for you on coins - I have yet to try it myself.

 

[DukeOBass]

I know from experience that Electrolysis will pit copper coins badly. You want to reserve this method for silver coins.

 

[king-ghidorah]

They used to say, put them in Extra Virgin Olive Oil, but I think I read here that this is not the recommended way. Did I read something about warm peroxide or something being the way to go? Please enlighten me. I have an IH and a LC that I don't want to blow the date off of - the ground has not been good to them and both are quite corroded - I can just about make out a date on each of them - Bob NH's Canadian LC cleaned up real nice - so what's the secret on cleaning these coins in the most gentle fashion? Thanks, Erik

Info can be found here:

 

[Great Republic]

Ya,electrolysis will pit your copper big time.GR