Cleaning a colonial

[jerseyjim]

I was detecting at this old school house, early 1800. I found a couple of Barbers and a few Indian heads. I came across this old very large coin,Bigger than a Quater, you can't read anything on it. I thought it was a slug at first. I did a light scrap on the end, it is copper or possible brass. If you look real close you can see the rim of the coin. I put it up against St. Patric"Halfpenny" that was in the coin book it was the same size. It is very hard to tell what it is. I put it in bleach that I heated up. I will let it site another few hours. Does any body have any ideas on how to clean it up? I know something is on there, it is raised a little.can't make it out.

Jimmy

 

[GKMan]

Probably your quickest choice will be a hot peroxide bath, put it in for a minute or or so and check it out brushing off any loose material, keep putting it back in until you don't see it getting any better, it sounds like the coin is pretty far gone so don't expect any miracles but maybe you can get an ID on it you can also use a flashlight to view the coin from the side to highlight any hidden details. There are other options like electrolysis or olive oil, some people cleaning while they are dry with toothpick,or even tumbling...
of course I would be remiss if I did not say if you think you have a valuable coin proceed with the utmost caution, or not at all

 

[jerseyjim]

I tried heating the Peroxide method. I will give it a second try with the electrologist method. Thank you. I think I will weigh it and try to find out what it is that way.
Jim

 

[azsh07]

Doing a rubbing of it also and see if that helps...if you are not familiar with that...simply put a piece of paper over the coin and rub it ligtlly wth the side of a pencil. You can also try a grease pencil or even a crayon.
Try different amounts of pressure and rubbing amounts to try and pull some details off of it enough to possibly ID it.

I would not suggest electrolysis for most coins....it really eats them up fast...unless you know it's toast and don't care and want a nice shiny coin.

You can try taking a soft brass brush and lightly cleaning it under water. Now I said a soft brass brush not a steel wire brush.....and never on silver coins. But on large toasted copper coins you really have few options to get detail that is simply to corroded.

The decision to clean or not to cean is up to you...people argue both ways but in the end it is your coin to decide. If you never try and clean a coin that is so caked with crud.. then all you have is a round blob of metal. So until it can be IDed...you have nothing really. Which is NOT to say go get a grinder and grind it raw. Rather try the least invasive methods first and see if you can get details.

Amazinlgy a good camera works wonders as well..easier to see detal on screen where you can manipulate contrast and brightness.

There are a bunch of old large copper coins around and many are colonial forgeries ( KGII's being the most widely forged coins at the time)...so sometimes weight and diameter will not nail it either but....it is one part of trying to ID it..

Many times just a few letters along the edge of a british coin or small details on a US coin and you can ID it. Does not take much......I have IDed many coins with just a smidge of detail

 

[ken ward]

OLIVE OIL: Let it soak in olive oil for weeks. YES ,, weeks.. Check about once a week and try to clean with a soft old tooth brush. I used a baby food jar and put in just enough to cover the coin. Mine was very green, You could not see anything. It took about 3 months to make it look good, but it worked. What do you have to loose if it takes a long time. Put it in and forget about it for a long time... KEN

 

[GKMan]

Doing a rubbing of it also and see if that helps...if you are not familiar with that...simply put a piece of paper over the coin and rub it ligtlly wth the side of a pencil. You can also try a grease pencil or even a crayon.
Try different amounts of pressure and rubbing amounts to try and pull some details off of it enough to possibly ID it.

I would not suggest electrolysis for most coins....it really eats them up fast...unless you know it's toast and don't care and want a nice shiny coin.

You can try taking a soft brass brush and lightly cleaning it under water. Now I said a soft brass brush not a steel wire brush.....and never on silver coins. But on large toasted copper coins you really have few options to get detail that is simply to corroded.

The decision to clean or not to cean is up to you...people argue both ways but in the end it is your coin to decide. If you never try and clean a coin that is so caked with crud.. then all you have is a round blob of metal. So until it can be IDed...you have nothing really. Which is NOT to say go get a grinder and grind it raw. Rather try the least invasive methods first and see if you can get details.

Amazinlgy a good camera works wonders as well..easier to see detal on screen where you can manipulate contrast and brightness.

There are a bunch of old large copper coins around and many are colonial forgeries ( KGII's being the most widely forged coins at the time)...so sometimes weight and diameter will not nail it either but....it is one part of trying to ID it..

Many times just a few letters along the edge of a british coin or small details on a US coin and you can ID it. Does not take much......I have IDed many coins with just a smidge of detail

I have had very nice results with electrolysis, never had one come out shiny like you mentioned. I have tried the olive oil for weeks on old coppers and you end up with either a nice coin, or a well oiled coin that is still encrusted...
Can you submit a picture of the coin? Perhaps with a flashlight shining from the edge.

 

[Steve O]

I've never had any luck with olive oil, even used extra virgin, soaking copper for months. The flashlight and paper method works best for me, after a brass brush, soap and water. Of course, this is for copper coins with no value, just for ID. Some coppers are just blank...they go in the toast bag. I've never had a silver coin that was not identifiable.

 

[azsh07]

Olive is hokum....plus...goo smell your coins that had olive oil on them 5 years later...blehh.

Electrolysis works fine...if you know how long and are careful....but it is the most aggressive cleaning form short of a grinder. I was not saying mever use it..rather not as a primary tool for ID.

Once you know either what it is or you know it is too fargone to be any value then maybe electro. But if it is a keeper and you electro it...well...anyone familiar with coins will spoy an electro coin. However it is each persons coin and theirs to preserve as they see fit///I personally care not what each person does with their own coins.

I only mention silver as I have had a friend take a brass brush and clean a silver coin. I thought the obvious truth of never cleaning a silver coin was so plain I never mentioned it. So I just mention it everytime Justin case.

Also slightly damp coin and shine a light from the edge works.

Really just a good closeup of the coin that is NOT overexposed and you can do a lot in photoshop. Since I use Photoshop a lot for design work I also use it a lot for coins.
One of the best uses is...once you have some reasonable features on it in the pic and have a guess as to what it is do this. Find a good pic of the suspected coin from the web. Download the pic and open it up in photoshop along with the pic of the coin you cleaned.

Drag the pic of the coin from the web and lay it as the top layer in the file of the pic you took. Now...size the pics so both the coins are the same size/ Align them to be proper rotation...ie top is top as best as can be suspected.
Change the blend layers so that you blend the two coins...usually overlay works good but whatever. You can then adjust opacity etc also. Now...you can see if exact features line up and they must in order to ID it..

I have dones this many times on coins or tokens that looked close to many others and once overlayed you will see what you thought was it does not match exactly.

Did this with a VERY worn Henry Clay medal...took a while but when I overlayed it...BINGO every feature that was visible matched exactly.
Of course you need at least photoshop elements...but down,laod it for free and see for yourself. Again many English coins and their American similar ....ie..Machine Mills..CT coppers etc.... can share features that look the same but won't line up especially on worn coppers where just a few features are left

 

[Steve O]

Photoshop....Excellent way to ID a coin azsh07...I like it...thanks

 

[Peter14K]

tried that before ended up with jet black round pucks. put em in coin holders and the oil began leeching back out. Olive oil is the worst idea of all suggestions above IMHO