What to do about corroded coins?

E-Trac-Ohio

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Feb 9, 2020
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Congrats on a FANTASTIC find !!! :occasion14:

If you don't already have one - I'd get a copy of the coin "Red Book" - only $15.00 to $18.00.
You can pickup a copy at you local coin shop or on the Internet.
Make a list of every coins date and mint marks - mint marks can be VERY IMPORTANT when it comes to value.
Then you'll know if you have any valuable "semi key date" or "key date" coins.
This will keep you from getting ripped off if you decide to sell the coins.

Good Luck !
 

eyemustdigtreasure

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Mar 2, 2013
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Hey all, brand new here... I recently unearthed 10 pounds of Morgan dollars, a few quarters, and some dimes, all dated from 1878 to 1915 or so. The coins were buried about 2 feet deep in a large glass jar with a wire cage to pin down the lid. I'm pretty certain the jar was already broken by the time my shovel found it, but I pulled out about 200 coins. I have a couple of questions...

The original owner of the property where these coins were found owned the property from 1895 to 1941. He was a boat captain (I have photographs of him and his registration card from the local marina) and I suspect he buried some of his money on his property. The next door neighbor has been here since the mid 50s and told me the kids that lived here after the captain found a double eagle under one of the trees in the back yard. I think there is a reasonable chance there are more buried jars. I'm looking for recommendations on a metal detector that will scan a couple of feet down.

Every single one of the coins has pretty heavy green corrosion and a few have dark purple corrosion. Pictures attached. I took a couple of the coins to a dealer and they told me the coins have been obviously cleaned and are only worth their melt value. It's certainly not true. I gently rinsed the coins in warm water to get the dirt off them and have them sitting in a jar. Many of the coins are stuck together. Is there any way to remove the corrosion without damaging the value of the coins?

Thanks for your advice!
Clad coinage?
Sort, then put each denomination thru a rock tumbler, with mix of water and grit, drain, fill up rolls, take to bank....! That's what I do.
If you get into the hobby big time, don't get a cheap tumbler.
By the way....FANTASTIC Find...!
What a story!
Voted Banner!

Welcome to TreasureNet!
 

brakeshoe

Tenderfoot
Apr 30, 2013
5
11
Philadelphia, PA
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SUPER AWESOME Find!! You have achived the detectorist's dream! Good Luck on cleaning and possibly selling them!
Hey all, brand new here... I recently unearthed 10 pounds of Morgan dollars, a few quarters, and some dimes, all dated from 1878 to 1915 or so. The coins were buried about 2 feet deep in a large glass jar with a wire cage to pin down the lid. I'm pretty certain the jar was already broken by the time my shovel found it, but I pulled out about 200 coins. I have a couple of questions...

The original owner of the property where these coins were found owned the property from 1895 to 1941. He was a boat captain (I have photographs of him and his registration card from the local marina) and I suspect he buried some of his money on his property. The next door neighbor has been here since the mid 50s and told me the kids that lived here after the captain found a double eagle under one of the trees in the back yard. I think there is a reasonable chance there are more buried jars. I'm looking for recommendations on a metal detector that will scan a couple of feet down.

Every single one of the coins has pretty heavy green corrosion and a few have dark purple corrosion. Pictures attached. I took a couple of the coins to a dealer and they told me the coins have been obviously cleaned and are only worth their melt value. It's certainly not true. I gently rinsed the coins in warm water to get the dirt off them and have them sitting in a jar. Many of the coins are stuck together. Is there any way to remove the corrosion without damaging the value of the coins?

Thanks for your advice!
Before listening to any of the treasure hunters cleaning tips go and post your pictures on a Facebook group for coin collectors. I read a few of them and cleaning is strongly discouraged but this may be an exception. Certainly do not but them in a rock tumbler as one person suggested. You need a coin experts opinion first. No disrespect to the treasure hunters here
 

tjdean01

Greenie
Aug 14, 2012
14
7
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Nice find. 10 lbs so maybe close to $2000 there in melt value, huh? Definitely get a metal detector!

The green is probably copper oxide. I'm not if this will help but vinegar corrodes copper so fast that wrapping a paper towel soaked in it will stop a small water leak (I've done it three times!). Try it on a coin that is only worth melt value and see if it gets rid of it.

A couple more things to try: if the corrosion is sulfur based, put aluminum foil and an inch of water in a saucepan, add baking soda, heat to a near boil, stir often. You might have to rub the foil on the coin because aluminum corrodes so fast that it is protected by a layer of aluminum oxide so you might need to rub it to get to the pure aluminum ions, which attract sulfur.

Also, make a paste with any type of vegetable oil, baking soda, a drop of dish soap, and a little water. This solution cleans caked on carbon from pans, I know and I don't know what it will do to a coin but if you have that stuff at home, it's worth a try.

Similarly, try Marvel Mystery Oil. That's never worked for me but I have it in the garage so if it were me, I'd try it. Also, WD-40 is NOT lubricating oil; it's a cleaner (but they don't want to tell you that because they make so much money selling it to people who think it is a good lubricant, which it really isn't). Try it if you have it. And anti-freeze also!

If any of these things works, you owe me a pretty picture of the results :)
 

Johnnybravo300

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Jan 3, 2016
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Oh yeah forgot to say those are worth much more than melt and id offer you more than that no probs haha.

Dentists have tools that could pressure wash those easily and not hurt them but they are worth more in original form and dirty than shiny and scratched.
For now just leave them be the way they are and they are fine.

You really have something there!
 

Emil W

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As a coin collector for the past 50 years I can tell you improperly cleaning them is far worse than leaving them as is. Rarely is a cleaned coin worth more than one with its original surface, tarnish and all, even when professionally cleaned.

I also believe the entire lot, sold as a whole including whatever is left of the glass jar, could be worth more if left as-is, uncleaned, because of its historical value. Talk to a local museum before doing any cleaning. Tell them the entire story and possible link to any potential original owner.

I'd personally sell the entire lot as-is, including its history, through an auction of historical items (actually, I'd probably keep them for my own collection).

As individual coins, assuming they are cleaned (and they do look cleaned in your photos), I agree with the dealer you showed them to -- they are worth scrap if you are selling them wholesale and if they are all common dates/mints. This is why I'd sell them as a historical find.
 
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Red_desert

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I got some feedback from treasure hunters, the old timer TNet members, who found ana sold their gold coins. You're coins are silver, so unless you find key dates this might not work. The gold coins were cleaned with acid, one group of coins the acid used was vinegar. Coins were sent to a place for grading without telling them about the cleaning. The coins got a top grading value which could not have happened if you mention "cleaned coins". If they asked you should tell them, but if not asked and the must be in good condition without looking as cleaned.

If you get it settled, the best way to clean silver coins, maybe try sending a few of the best for coin grading.
 
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pepperj

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Just input 4536g @90%= $2900 5% spread.
 

Emil W

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I got some feedback from treasure hunters, the old timer TNet members, who found ana sold their gold coins. You're coins are silver, so unless you find key dates this might not work. The gold coins were cleaned with acid, one group of coins the acid used was vinegar. Coins were sent to a place for grading without telling them about the cleaning. The coins got a top grading value which could not have happened if you mention "cleaned coins". If they asked you should tell them, but if not asked and the must be in good condition without looking as cleaned.

If you get it settled, the best way to clean silver coins, maybe try sending a few of the best for coin grading.

Your friend may have received a 'top grade', although I'm sure the grade was more specific than that, but by soaking a gold coin in vinegar all he did was remove what's generally called 'toning'. Collectors normally prefer toned gold -- which gives the coin a rich, natural look and serves as proof the coin is uncleaned -- over coins without toning. In other words, most collectors would have preferred the toned coin. The grade he received would even have noted that the coin was toned, had he not cleaned it before sending it for grading, which would have been a positive and would not have lowered the grade.
 

Red_desert

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In that case, don't clean gold coins, just send them in for grading.
 

Red_desert

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I heard one story, guy digging for new outhouse, broke jar of gold coins. They took the gold coins right to a coin dealer (dirty, broken glass, bloody) and got the money.
 

UnderMiner

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I heard one story, guy digging for new outhouse, broke jar of gold coins. They took the gold coins right to a coin dealer (dirty, broken glass, bloody) and got the money.
Gosh I wish I was that coin dealer. Give the dude melt value for some rare California double eagles.
 

Red_desert

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Gosh I wish I was that coin dealer. Give the dude melt value for some rare California double eagles.
Yep... :coffee2:
 

flinthunter

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You might try the warm water soak. Do not rub the coins. Pat dry with a soft cloth only. I've heard that using pure acetone will remove corrosion without harming patina or toning but I have never tried it. You really need to talk to an expert before trying anything. There are probably coin groups on facebook that can guide you through this. I know it's a rush to be able to brag about a great find like this but the IRS does monitor these type of sites.
 

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