Salt Water Silver Coins Cleaning

Rick (Nova Scotia)

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May 8, 2008
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Silver coins from salt water enviroments can be very tough to get clean. The build up, and the black just won't come off it seems with any one method. The ship wreck coins usually go through many different treatments including electrolysis, which I don't care for as it tends to like to pit things of copper / silver. Not to mention that isn't necessary.

I found this combination of things work well, and relatively quickly.

#1, a soak in 10% solution of muriatic acid, don't be too concerned about exact percentages here, and slowly put acid in water not other way round. I let this soak for a day. Perhaps less time is enough, but it will not hurt the coin regardless. and this is the first step that the ATOCHA coins had done to them, although I think they said 10 or 20 minutes.

This tended to removed the real crusty looking stuff, but the black remained.

#2, The tin foil method, while this seems to little all by itself there is definitely something going on here. Wet the coin, and tinfoil with a solution of baking soda, and water. wrap the coin shinny side of foil toward the coil, and press tight with your fingers or place it under something, the goal is to make contact, as in electrical. Leave a couple of minutes this way 2 to 3 is enough.

#3, rub the coin with ordinary table salt, and just enough drops of water, you'll know how much, add salt, and drops of water as necessary. You will see the black comming off.

Repeat steps 2 and 3 as necessary or untill desired color remains, or is completely "new" looking silver. In my case with these two coins it was 3 repeats of step 2 and 3.

I've done other too, that were near unrecognizable to looking like new, just don't have before pics, so little point to show them

I WOULD use this on a rare coin too.
Please reserve negative comments about how I ruined the value here.

Before.

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After.

IMG_1085.JPG
 

Can't believe I got no replies , with so many asking for advice..
just give it a try, on something without value. and you will see this in fact does work.
 

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Any recommendation for copper coins and buttons with similar salt water corrosion?
 

I may have to try the 2nd part on a seated dime I have. Thanks for sharing. Do you recommend the boiling peroxide method for copper?
 

I may have to try the 2nd part on a seated dime I have. Thanks for sharing. Do you recommend the boiling peroxide method for copper?

Aftrer a quite a bit of experience with old coppers I like to access the amount of corrosion first, if no corrosion, you can peroxide till the cows come home without any problems, the more corrosion the coin has the more carefull you should be, and maybe best not to heat it up, just use cold with Q-tips.
Coins that have a sharp edge, (or even a rounded over edge) are heavily corroded. The ones that have a sharp edge, but still have some detail, I usually quit after just a rubbing with my thumb.

As has been argued before peroxide won't hurt the copper, but if the only detail remaining is in the corrosion, and it really is a blank copper disk underneath, then that "false" detail (for lack of a better term) could come off.

I'll make a drawing to add here, but I need to go dig some holes right now.
 

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Thanks for the quick reply, Good Luck on your hunt.
 

Thanks for the info! Can't wait to try. I have destroyed some with electrolysis. I have some Barber dimes to try it on. I will try to do before and after pics. Thanks again.
 

Silver Atocha coin

I want to clean my real Atocha silver coin, not concerned about "ruining its value." I bought it because I loved the piece and wear it as a necklace. I want it to be more silvery/shiny. My question is, if I use any of your recommended methods, will it harm the 14k yellow gold with small diamonds surrounding it? I need to clean the salt water and waterproof sunblock off of it that made it look dull because I've worn it everyday for a few years and spend a lot of time swimming in the Gulf of Mexico. I made the mistake of asking a jeweler to polish it, not knowing he would use a wire brush on it! After that, there's a dark gray spot on it.
 

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Troyprofessor, if your coin has just some "new" gray from salt water, and maybe some sun screen on it, then maybe just all you need is some solvent (alcohol, acetone etc.) to remove the sun block, then a dip in coin dip, available at any coin shop.

Hard to believe any "jeweler" would use a wire brush. ??
 

I have several 8 and 4 Reales that I'm going to test the muriatic dip on...starting with the worst one first. Will try lemon juice once I get the major growth and corrosion off. Thanks
 

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