Here's a tip for treating crusty copper coins... (The Potato Trick)

lordmarcovan

Brush as much of the loose crud off the coin as you can. I use a fine brass wire brush (made for cleaning electrical components, I guess- it says "Lincoln Electrical" on it and is slightly bigger than a toothbrush).

Then stick the coin overnight in a raw potato.

When you come back to it in the morning, you'll be surprised at how much black-green gunk the starch in the potato has leached off the surface of the coin.

Brush again, repeat the process as necessary.

As you brush, the coin may begin to show bright copper on the high spots. You can retone it back to brown by using a paste of powdered sulphur and Vaseline.

Now, the question is, where does one get powdered sulphur? I got mine from a friend. I'm not sure if it is used for some pharmaceutical reason or not. I think it's maybe used in gardening? So maybe a garden supply place would have it.

AuldFartte

LordM: IMHO, if the copper coin has any potential value as a collector coin, I would avoid the wire brush like the plague! If it's grungy and crusty, but the diameter of a US Large Cent or Half Cent, I'd soak the crud loose in virgin olive oil and lightly work the stuff off with a Q-Tip and use a rose thorn for the deeper areas around devices. The potato sounds interesting. I will try that

lordmarcovan

Good point. I thought the caveat about coins with potential collector value didn't need to be said, but he's right- you don't wanna go wirebrushing a Chain cent, folks! (Edited to add: I use a brush with very fine brass bristles- not as bad as it sounds).

The olive oil is a tried and true (if excrcuciatingly slow) process, and I intend to start using the thorns like you suggested, rather than toothpicks, which are too soft.

I used the olive oil and the potato method on this. No wire brush, of course.

gargoyle62

So the olive oil method is valid? I found an1888 canadian cent in a bag of SAC's at work, and decided to try the olive oil treatment since it's basically black except for the high spots. After leaving it in there for a week with no noticeable difference, I figured that somebody posted that just to have fun with us newbies. Maybe I'll try soaking it for another week and then stick it in a 'tater and see what happens.

lordmarcovan

The olive oil method can take a very long time, sometimes, and in my experience doesn't have much effect if your coin isn't covered in loose, crusty crud. I've found the 'tater to be quicker.

gargoyle62

The 'tater treatment is working like a charm. I'm completely amazed. Thanks for the tip.

granddad

I have also had good luck soaking crusty copper in sewing machine oil. As for the powered sulfur, it is used in agriculture in the rare instance when you need to lower the soils Ph level.

Louis

Like the tater method, will try that.

ms70

LordM, the 1798/7 Draped Bust cent you found in the forest- Was it just out in a forest or was there a settlement there at one time?

SPEEDracer

Good tips...Thanks. Question though. When using Olive Oil...don't you have to use smoe sort of solvent to get the oil off the coin?

lordmarcovan

<< <i>LordM, the 1798/7 Draped Bust cent you found in the forest- Was it just out in a forest or was there a settlement there at one time? >>



Man, I wish I'd been the one to dig that! I just bought from my detecting buddy- he was the one who found it. Had I dug it, I would have kept it. I sold it for around $775, as I recall.

The site was almost certainly an old house site, long since disappeared and grown over by piney woods. That's the way most of the relic sites down here are- the sites where the really sweet coins come up.

goldrush00013

grip

Coca Cola,as well as olive oil works,the olive oil sometimes takes eight months or more,I also
have used C L R,with fairly good results.
Al

Coinerww

If you put the coin in the potato is that considered cleaning the coin?

lordmarcovan

Yes.

IndianHeadMan

the potatoe thing didn't work for me. The caked on dirt that wouldn't brush off was uneffected.

lordmarcovan

Some respond well, and others don't. Might have somethin' to do with the sort of minerals deposited on the coin.

sellsatan

After reading this thread I just realized that I put a handful of coins in a tub of olive oil about two years ago and they are still there. I have two houses (next door to one another) and the tub in question is in the other house (which explains how I forgot about it). The other house is what you might charitably refer to as "a work in progress" and is not heated through winter. I am certain that the olive oil has frozen and thawed several times over two years time. Add to this the fact that the coins in question are of various types and metallic compositions (nothing woth worrying about, a few wheats, a few mercs, a '64 Kennedy and maybe a silver quarter or two) and I have to wonder what I will find when I go get them. Any predicitions?

CROCKofCOINS

It would be nice to see a photo of what you find

Jerry

CoinOnTheCob

<< It would be nice to see a photo of what you find >>

No, kidding. I'd like to see what affect two years of olive oil soaking could have. That is thorough.

lordmarcovan

<< <i>Add to this the fact that the coins in question are of various types and metallic compositions (nothing woth worrying about, a few wheats, a few mercs, a '64 Kennedy and maybe a silver quarter or two) and I have to wonder what I will find when I go get them. Any predicitions? >>

I predict the silver coins will be a funky color. Why would anyone put silver in olive oil? Were they encrusted?