Cleaning Shark Pit Cookie Coins using electrolysis

[djabend]

First I want to thank rtde3 for letting me try electrolysis on some of his Shark Pit cookie coins.
and for the shark tooth

With It were 3 cookies

quarter sized these are usually standing liberty or barber quarters

penny sized with that copper green crust, usually an indian head or wheat penny

dime sized most likely a merc or a barber dime
first order of busyness was to make a contact point on each of the coins, bare metal for current to past through
I accomplished this in short order with a dremel and dentist pick.

quarter

dime, I could tell delamination was going to be an issue here if i was not careful more on that later

penny
Once cleaned it is time to make your electrolyte solution(I use vinegar for silver and baking soda for copper)
and hook up your power supply (I use 9V 300mA) copper anode for copper and in this case I was using a pull tab
anode for the silver (I found a use for them!)
The silver coins gave off a white substance when zapped. Something was leaching out of the crust.

After a few hours off and on of treating the crust will start to soften.
From here the crust must be manually removed..... and here it gets tricky
The following pictures are not pretty
DELAMINATION- the coin comes apart in layers losing detail and if you are not careful the whole coin

I was able to save the rest of the coin and get the date but much was lost


The dime was holding up better at this point and was probably the best preserved of the bunch
The penny...... we wont go there
I will post the finished pictures in the next post
What did I learn?
1.These coins are highly unstable due to what I believe is copper loss from up to 100 years in the water.
2.The coins are porous because of this and soak up water. The more they soak the more they can delaminate.
3.Go slower the coins aren't going anywhere
4.It really sucks when the edge snaps off a SLQ
5.rtde3 is the man!
6.Whites metal detectors are the best ( lol I am going to get it for putting that one in.... )

It was a great time seeing these old coins that come from such a cool place in person and being able to work on them.
rtde3, best of luck hunting the Shark Pit! HH,
                                                               Donny

[djabend]

Here are the finished pictures

1917 Standing Liberty Quarter


1907 Barber Dime


19?? Wheat Penny



HH,
     Donny

[rtde3]

Good Job Donny! You did better than I have on most of these! I'm glad you had fun with them! ;)

[BuckleBoy]

I have a question about this...  How do wreck divers get their Spanish silver and copper so clean???  If the only way to clean such saltwater finds is electrolysis, why do I not see Spanish coins looking like this after cleaning?  They've been in the water much longer, after all. 

Perhaps someone with diving and recovery experience will also comment on this thread.  Grubby?

Best Wishes,

Buckleboy

[djabend]

I have a question about this...  How do wreck divers get their Spanish silver and copper so clean???  If the only way to clean such saltwater finds is electrolysis, why do I not see Spanish coins looking like this after cleaning?  They've been in the water much longer, after all. 

Perhaps someone with diving and recovery experience will also comment on this thread.  Grubby?

Best Wishes,

Buckleboy

I am sure there are other ways to clean crusted sliver and I am only just learning about electrolysis. I think Grubby said he used a mild acid bath,
but I could be wrong. HH,
                                   Donny

[rtde3]

That's a good question BuckleBoy. I have a Spanish cob I bought off someone & it was not crusted just real black. You clean them with lemon juice & alum. foil. I think the Bay has so much run off of nitrates and other stuff from farms & lawns... that this might have something to do with it. This is for sure why the bay has been dying for the last 30 years or so. There has been a big "save the bay" program going forever it seems like. The sea grasses, crabs, oysters and many other things that live in the bay have been disappearing for a long time now. And all these cookie coins were found fairly close to shore in the bay. So my guess is it's a "Bay thing". I have found Clad coins at another spot in the bay that had a light crust on them & if they had been there for as long as the cookie coin they would proably have a thick crust on them. I have never seen cookie coins come from any where else. Just my guess, I could be wrong.