| Author |
 Replies: 10 / Views: 11,386 |
|
|
Valued Member
United States
327 Posts |
When searching penny rolls, I often see dried deposits on newer pennies. It looks like they were splashed with something. I see it all the time in every box I search. I was wondering if it might be some type of liquid residue used in the stamping stage. Maybe some kind of oil. It doesn't rub off but I was hoping there might be a way to remove it from a coin that would otherwise look very nice. I think I was told a long time ago that even water is not recommended or any type of cleaning for that matter. Has anyone else seen these spots?
|
|
|
|
Moderator
 United States
56855 Posts |
Very common on newer coins. It has something to do with the final wash at the mint. I don't know if you can clean them off. I have seen plenty in my days.
John1 
|
|
Valued Member
United States
368 Posts |
all over almost every new penny I see
it ruins so many BU's I think I've found
no idea what it is or how to get rid of it
I just reroll these and dump 'em
|
|
Bedrock of the Community
United States
19930 Posts |
It's residue from the metalworking fluid and/or post-rinse used during the coining process. During any type of metalworking process the fluid sumps become contaminated and unbalanced over time. Eventually, soaps form due to the interaction of metallic ions (copper, magnesium, calcium, etc.) in the water and fatty acids used in the fluids. These soaps can strongly adhere to metallic surfaces forming a semi-permanent bond and create a residue, i.e. spots. Once fully dried, the spots are irremovable without damaging the coins surface.
The nice, spot-free gem coins that are found by searchers are mostly likely those that are coined while the fluids are fresh. Since billions of cents are produced I suspect the fluids are used for many months before the systems are dumped, cleaned and recharged. In fact, it may even be several years. We have one major customer that runs their 20,000 gallon central fluid system for 5-6 years between dumps.
|
|
Pillar of the Community
United States
2541 Posts |
I've noticed the same thing and haven't bothered to save any 2009 or 2010 with the spots. Coins without the spots have definitely been harder to come by.
|
|
Valued Member
United States
162 Posts |
Does anyone know if something like acetone would remove the spots? Would it damage the coin in any way?
|
|
Bedrock of the Community
United States
19930 Posts |
Did you read my post? The spots are irremovable without damaging the coin. The only way to remove them is with acid, which will ruin the surfaces.
Lincoln Cent Lover!VERDI-CARE™ INVENTOR https://verdi.care/
|
|
Valued Member
United States
162 Posts |
I did read your post, but you also said they were caused by fatty acids which I believe acetone can safely remove and that the bond was semi-permanent which also implies that they can be removed. This made me think that even if you didn't know how to remove them that maybe someone else in the forum would know how.
|
|
Bedrock of the Community
United States
17884 Posts |
These spots are probably similar to the "milk spots" that appear on the silver eagles. So far no one has managed to remove those and the TPG's have offered thousands of dollars reward to anyone who can do it. And copper is more sensiive to appearance change than silver. So far the only thing that has seemed to work at all has been an acetone rinse before ay spots appear. (Of course that begs the question whether or not the spots that weren't there in the beginning ever would have appeared.) |
|
Valued Member
 United States
327 Posts |
Well, at least I don't feel like it was just me now!! By far, the majority of the 2010 cents I have found in rolls, have this residue. Maybe this is a good thing as it will provide a premium for cents without the spots...
|
|
Bedrock of the Community
United States
19930 Posts |
Yes it does....unfortunately. Looking at my MS-67 slabbed coins from 2009 the grading is 90% based on spotting. It's sad actually because some of the 67's have significant hits. I cracked a good number of 2009 OBW's and found coins far superior to my slabbed 67's as far as hits....some nearly flawless, but they may have had a few more light, black spots. IMO, the HITS should dictate the grade over spotting. This is a big mistake by ANACS, NGC and PCGS....grading moderns by spots. On another note, none of the TPG's can accurately grade modern cents. They all consistently mis-grade AU coins as MS. I've seen it over and over and over. Lincoln Cent Lover!VERDI-CARE™ INVENTOR https://verdi.care/
|
| |
Replies: 10 / Views: 11,386 |
|
Posted 07/16/2010 8:46 pm
