3 nice commemorative halves (1892/93 Columbian, 1925 Ca. Jubilee) Sticky residue?

Hi Everyone -

More adventures in sorting this little coin stash

I found these 3 commemorative halves - an 1892 & 1893 Columbian expo, and a 1925 California diamond Jubilee.

All look beautiful to me, but look like at one point there was tape or something on them that was removed - Hard to see in the picture but each has a half inch stripe on the back that is a bit cleaner than the rest of the coin.

Can this be fixed? Not as noticeable on the 1925, and that seems like a beautiful coin otherwise. I hear acetone dipping will help but I have also read to never do that - Would love thoughts as I think these are really cool!

 

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There is nothing wrong with soaking a coin in acetone, as long as it's pure acetone (like what you can get at a hardware store). The acetone will remove any residue from the tape that may remain on the coin if it is from tape.

Having said that, stripes like that are often not from tape but from older style paper holders that collectors stored coins in. The coin tones differently around the paper strip. This type of toning is often accompanied with pleasant toning, and the strip does not detract from the appeal of the coin. The only way to remove the toning would be to dip the coin.

If the coins are sticky, I would soak the coins in acetone (make sure to do so in a glass container as acetone will dissolve plastic) as this will remove any remaining residue, but would otherwise leave them alone.

 

What @Jaelus said

 

Ill try this! Do you just dip it for a few min?

 

Do not do it inside. Be careful.

 

There are a couple chemists on CT and there have been some good "how To" threads posted in the past. Search the archives

 

Meh...acetone isn't that bad, flammable so keep flames away, if you were doing a lot, you might worry. First give it a couple of minutes, then extend it slowly till you get the results you want.

 

I always do my acetone soaking inside, that way it's in a humidity controlled environment and you don't have to worry about tiny pieces of debris floating on to the coin. Just make sure you have adequate ventilation.

It also helps to soak the coins in sealed containers. Acetone evaporates very quickly so by sealing the container you can do a longer soak. You also do not want to let the acetone evaporate while a coin is soaking because the contaminants removed from the coin will not evaporate and will be redeposited back on the coin.

I use this type of container:

https://www.bedbathandbeyond.com/st...-piece-container-set-in-clear-blue/1062309844

 

I usually use a shot glass and put something on it as a cover...

 

I've used a shot glass now and again, but they are too small for larger coins and medals and too small for dipping (no room for tongs or a basket).

 

If not too often, I just use my fingers. Acetone has never hurt meeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

In all seriousness, do limit your exposure.

 

I use my fingers for acetone as well, but not for dips.

 

I have used acetone for a bunch of projects before and Im pretty careful with it - My dad was a builder so that stuff was always around in one form or another!

 

My stepfather used to claim that so many painters were alcoholics because of their repeated exposure to solvents.

 

Could that pertain to Chemists as well?

 

That's good. If not, you would have to rely on what you were supposed to learn about handling chemicals in High School Chem Lab

 

The only thing I will recommend is use glass only no plastic no plastic gloves and when you finished with the dipping and soaking do multi rinses with disstilled water and Pat dry don't rub

 

Acetone is used to dry things quickly. The coin will already be dry and you shouldn't have need to pat the surfaces dry. You do want to use an acetone rinse after the soak, to make sure no contaminants that were in the acetone are left on the coin. You can also use another clean container of acetone to swish the coin around in. If you add water after an acetone soak all you're doing is making the coin wet which will dry very slowly.

 

The acetone will remove the sticky residue, but the stripe caused by the uneven toning will remain.

 

I resemble that remark...