Proper Conservation of Copper Coins

DeutscherGeist

Dear Coin Crusaders,

I have some copper pennies (Indian Head, Lincoln), large penny (King George) and various coppers from Germany (Kaiserreich, Third Reich). Some have very nice details on them while others have accumulated crud.

Dipping them in acetone for a short while and using a q-tip carefully should give it a safe once over?

What else is there to do? What other proper solvents are there?

Gazza

Acetone can leave a purple tint on copper, treat with care. A drop of liquid soap and water with a dab dry with lint free cloth is fairly safe, absolutely no rubbing.

brg5658

I agree. I'd stay away from Acetone on copper. I have not had good luck and have ruined a couple coins (not expensive ones thank goodness).

DeutscherGeist

I keep hearing about the NO RUBBING, but what does it entail?

Is the goal to avoid scratches and hairlines?

Gentle rolling with a 100% cotton swab while immersed in acceptable liquid is safe. Am I missing something?

7Jaguars

I suppose it confuses the issue, but I have NOT had a problem with acetone and copper. However I use the gentle rollover with a Q-tip or tamping with a clean high nap white cotton towel that has been soaked in 100% acetone. Then gentle rinse with mild soap and LOTS of water with a tamp dry with clean white towel of same sort. No problems and have some top pop coins that have been treated that way (RARITIES at that).

I do not just leave the coin to soak and hope for the best like I have seen advocated on some columns. Prolonged exposure may be an issue.


As a pet peeve, I HATE copper cleaned with MS70 and a few others that leave the blue-purple residue. I have seen a number of these in "prominent" TPG holders and collections....

DeutscherGeist

I do not see how a coin can have hairlines or scratches by using a q-tip that is soaked with acetone. I think acetone on copper for a short period is fine. Prolonged exposure causing a purple hue maybe due to the surface contaminant that the acetone is reacting with? A brand new copper coin might not have a reaction at all to acetone. An old copper coin might because of the patina and other crud on the surface (I wonder what the verdict is on that).

Acetone evaporates quickly. A rinse in super clean acetone is all that is needed. One needs several dip dishes with the last one being the final rinse.

I heard of dish washing soap can also be used. I know that it takes off a lot of contaminants and waxy substances.

How about olive oil. I heard that copper dipped in olive oil for a month helps loosen the crud. I am uncertain about this technique.

BRG5658,

Your technique is confirmed harmless if you are getting your coins passed the graders. I mean, these are metal coins, not baseball cards. There is some durability in them.

theboz11

I use acetone routinely and have tried olive oil only a couple of times on medals. It did lift the majority of crud and did not turn the pieces in color like products such as MS-70 and other soapy cleaners will.

I occasionally use "Blue Ribbon" as a preservative. Acetone will take all the oils out of a piece and leave it lifeless so to speak, Blue Ribbon returns some of that oil.They used to use varnish.

Gazza

<< <i>I keep hearing about the NO RUBBING, but what does it entail?

Is the goal to avoid scratches and hairlines?

Gentle rolling with a 100% cotton swab while immersed in acceptable liquid is safe. Am I missing something? >>



I have seen people clean a coin by whatever method then put in in a towl with thumb finger either side and rub between their thumb and finger. It can scratch and leave hairlines if the towl is coarse.

ColinCMR

rose thorns are useful for picking out dirt and grime

LochNESS

<< <i>rose thorns are useful for picking out dirt and grime >>


Interesting! No matter how many times we discuss cleaning, something new always pops up.

YQQ

Hawthorns are the best. Much better than rose thorns.
Unless the coin is MS grade, Immerse the coin into Hot water for about 10 minutes. It will loosen the crud. Then use a soft old tooth brush and if needed a pointy hawthorn

MacCrimmon

<< <i>Hawthorns are the best. Much better than rose thorns.
Unless the coin is MS grade, Immerse the coin into Hot water for about 10 minutes. It will loosen the crud. Then use a soft old tooth brush and if needed a pointy hawthorn >>




No matter the thorn(s) available be sure to use those that are still very green so as to minimize potential scratching.

YQQ

Hawthorns are stronger and do not break as easy as rose thorns.
also , either thorn is softer than copper or silver and hence does cause damage.

terribleredmonster

Whatever solvent you decide to attempt, do not trust your tap water for a clean and even rinse. You need distilled water, preferably in three containers for a three stage rinse. Otherwise, stuff you don't even see after the operation turns over the next several months/years into ugly, nasty distractions. This may be more true on silver than copper, but both are fairly reactive.