bought this Austria Salzburg taler last September at the Superior Galleries Pre-Long Beach auction. I opening the sealed flip (Seems like Mylar to me) it was it carefully and with cotton gloves took a couple of photos, put it back into the flip (unsealed at this point) and put it in a hard plastic slab box (It has a few other coins in it also) and then put it in my safe deposit box at my bank ( I keep a dessicant bag in it) Yesterday I went to retrieve a few coins I submitting to NGC, this taler being one of them, and this is what I found BEFORE: NOW: The obverse hasn't changed !!!! Any suggestions of what I should do ... or if I should do anything !!! I wondering if a quick dip in acetone will clear this toning (if that is what it is) or don't bother and get it slabbed a quickly a possible in an attempt to keep the spot on the coin from darking any more. What ever I do this is a great looking/condition coin and I don't want to get this coin BB at NGC!! Thanks in advance for any feedback!!!!!!!
If you look at the area that has blackened in your 'before" pic you will see that it was a bit lighter than the rest of the coin.I suspect that whatever caused this lightening,possibly cleaning chemical,has reacted with the silver and air to cause this rapid tarnishing.I couldn't begin to tell you how or if to remove it without harming it's value but maybe some others on here can.
You sound like a very careful person, so this may not apply. Dessicant bags or cartridges will absorb moisture up to a certain point; then may become a contributor of moisture into a safe or box. Most come with instructions as to how to renew their absorption capacity ( usually by heating in a dry environment. Many people are not aware of this and never renew the dessicant. Many of the cartdriges change color when "full " and to a different color when " dry ".
Banks are known for keeping the humidity high to protect paper documents. So if you didn't change the silica pack every couple months that may well be the problem. It may also be because the coin was previously dipped. As for the grading, I think it might well be body bagged. Only way to find out is to try.
NCS with photos they seem to think it is caused by a fingerprint (or I guess more so by what was on the finger) and they may be able to help and barring no improper cleaning or evironmental damage get it NGC graded. Regarding the general condition, obviously the coin has been cleaned (Via a dip) since 1794, but in hand I can see no signs of any harsh cleaning or wizzing ( w/16x loupe) and the coin does have some lustre. The field marks are normal wear/tear and planchet graininess (I guess thats the proper description). So off to NCS/NGC it goes and with a little luck it will come back in an NGC slab with a AU-58 or higher grade :whistle: Thanks for all your comments PS: I do try to change out the dessicant bags every six months... I might change to every qtr.
I am no expert, but my vote is that it was dipped to pretty it up for auction, and this is the result.
I agree with you JBK. Doug, I'll try to do better... I only have a few silver coins in flips (soon to be airtites... I know they're not really air tight but I assume a great improvement) Should I be concerned about slabbed coins ...silver and gold ????
Hi, I absolutely think the coin was cleaned before the auction. I think that the particular spot as mentioned in an early post was doctored. If it is not just the picture, You can see some very dark to black coloring on the very edge of the coin where the edge meets the rim between 2:00 and 3:00. (the pre-toned pics) I think that after the coin was put away, the tarnish crept back up on the area that had previously been cleaned. I don't believe it iwas due to a fingerprint as most of the time, the tarnish takes on the form of the print and looks like a fingerprint. It doesn't usually look like a big black spot. I think that a professional grader will body bag it because the cleaning was obvious and the tarnishing does not resemble a fingerprint. Bill
JBK,you're right.Although this Salzburg Thaler has been cleaned,it is actually a very good piece to fill a space in your collection,especially if you are collecting coins from the Austrian states,or any of the German-speaking countries in Europe. Aidan.
What happened chemically to that coin? What chemcials might someone use to "clean" corroded coins? What do you think caused the distinctive color change? I wonder if the coin had some residual chemical on it? I would have assumed that metal being just metal, that some residual corrosive chemical must have caused the color change. Do these dipping compounds selectively remove one or more base metals, and leave silver near the surface? Does a dipped coin become porous on the surface? What would bank-vault moisture do to a coin in the absence of some corrosive or oxidizing gas or salt? Clearly, your average 500-year-old coin did not lay around in an air-conditioned bank vault. Interesting.
What sometimes happens with a dipped coin is that they are not rinsed properly afterwards and some of the dip solution remains on the coin. At first it's not visible, but given time the solution acts on the metal and cause very dark toning much like what we see here. Humidity tends to accelerate the process and can even make it worse than it was to begin with.
