Verdigris on higher grade coins
Posted: Wed Jan 18, 2012 10:01 am
Hi all,
I have been storing pennies in 2x2 flips for the past 3 years or so. I have coffin boxes that hold 2 rows of 2x2 flips for easy storage and safe keeping. These boxes have been in trunk in a room on the 2nd floor of our house. Exposure to temp extremes and moisture would have to be low IMHO.
Anyways I was reorganizing the flips and noticed that a coin of mine 1931-D (stored in a hard plastic single penny holder) was starting to show signs of verdigris on the obverse. I was more than shocked to see this occurring on a coin in a hard plastic case. Although i cannot be certain I believe the green patches must have formed only over the last couple years. So what's wrong with my storage? I barely slept last night going through half of my collection. And found a couple other examples where coins look like they are either toning or have what can only be described as sweat patches (i'm particularly concerned about a 1909 vdb that is xf+).
I have also taken steps to remove any coins with verdigris on them from the rolls and now i'm trying to figure what's the next best thing to do with the coins that have verdigris on them. I looked through pages of flips and found NO corrosion. Could airtight plastic coin cases and tubes be the cause of this?
Attached below are examples of what I saw last night:
Please note my 31-D is in much better condition and does not have the craters.
What can be done to a coin that is starting to show signs of verdigris? Most of the coins would be valued less than $5. I've been reading up about cleaning coins by (found athttp://metaldetectingworld.com/cleaning_coin_p6_mechanical.shtml:
1. soak in olive oil for 24hours
2. neutralize by bathing in acetone
3. brush with tooth brush and toothpaste
4. rinse / soak in water
5. dry in oven or other low dry heat source
Any help, comments, advice will be great. I've got about 15 IHC's that i'm going to try various method of cleaning to see which method does the job best without totally destroying the coin in the process.
~JobIII
I have been storing pennies in 2x2 flips for the past 3 years or so. I have coffin boxes that hold 2 rows of 2x2 flips for easy storage and safe keeping. These boxes have been in trunk in a room on the 2nd floor of our house. Exposure to temp extremes and moisture would have to be low IMHO.
Anyways I was reorganizing the flips and noticed that a coin of mine 1931-D (stored in a hard plastic single penny holder) was starting to show signs of verdigris on the obverse. I was more than shocked to see this occurring on a coin in a hard plastic case. Although i cannot be certain I believe the green patches must have formed only over the last couple years. So what's wrong with my storage? I barely slept last night going through half of my collection. And found a couple other examples where coins look like they are either toning or have what can only be described as sweat patches (i'm particularly concerned about a 1909 vdb that is xf+).
I have also taken steps to remove any coins with verdigris on them from the rolls and now i'm trying to figure what's the next best thing to do with the coins that have verdigris on them. I looked through pages of flips and found NO corrosion. Could airtight plastic coin cases and tubes be the cause of this?
Attached below are examples of what I saw last night:
Please note my 31-D is in much better condition and does not have the craters.
What can be done to a coin that is starting to show signs of verdigris? Most of the coins would be valued less than $5. I've been reading up about cleaning coins by (found athttp://metaldetectingworld.com/cleaning_coin_p6_mechanical.shtml:
1. soak in olive oil for 24hours
2. neutralize by bathing in acetone
3. brush with tooth brush and toothpaste
4. rinse / soak in water
5. dry in oven or other low dry heat source
Any help, comments, advice will be great. I've got about 15 IHC's that i'm going to try various method of cleaning to see which method does the job best without totally destroying the coin in the process.
~JobIII