What do you guys think of the toning on this cent? Is it pre-slab or progressive? Is it common for toning to occur after grading moderns? Do grading companies do anything to try to inhibit post slab toning?
Progressive.... Slabs are not air tight. I once had a beautiful MS65 SLQ grow a black spunge inside its slab. I have a few early coppers graded by NGC and they tell me that the grade only applies for ten years on copper. After ten years I have to send them in for another evaluation because copper is so reactive to the environment.
Copper starts to tone the moment it is struck. Slabs can slow it down but not stop it. I know a few collectors that don't collect red copper because of it. I have a lot of cents in slabs that have gone from red to RB and even to brown over the years. Not a good thing as far as value goes.
These 09' cent's are known for toning very quick. The whole set I had toned and not very attractive either. Here is the formative years.
I saw someone else mention this here, one of my other threads, I think. I don't understand how a grade can expire after 10 years. There is no date on the slab. How would you know?
I've seen this mentioned here on CT also, but didn't realize it was so common. Can't the coin be prepared better to avoid this problem?
Is it a fingerprint on the reverse? Is it mishandling? The obverse looks like something burned it. Would acetone wash prevent any of this toning?
No the reverted back to the pre 83 composition for these coins. They are just very susceptible to toning. An acetone wash isn't going to help. And in a lot of cases optimal storage conditions doesn't even help. Note that this doesn't seem to happen to the Bus strikes. It only happens to the PF's. Could be the packaging that was used.
It might even make it worse as it would remove any oil film that might be on the coin that could help protect the copper from the air. After the acetone the bare metal is exposed to possible reaction.
