Quite possible they think wood grain effect was artificially applied to the coin. It's not as uncommon as you might think.
On a Large Cent, I would describe it as microscopic porosity. What others call bevelled planchet, I call thin planchet. I have a 1866 with this among several errors.
More of the classic TPG cop-out crap. They just don't want it in a PCGS holder, it is definately NOT artificially colored. I've seen it plenty of times. The 1920-S is a tough coin in mint state....99% of them look like crap, like they've been cleaned and retoned. That's just the nature of the issue due to the planchets/processes they used. I've turned down every MS 20-S I've seen because they are so nasty looking, slabbed or not. They just have the look most Lincoln collectors reject and I don't want to be stuck holding the bag on one because they are not cheap.
I should add again....your 20-S is actually VERY nice compared to the others I've seen. Can you see any luster on it? I would have broken it out of that body bag slab within 5 minutes of getting it. LOL
It has some luster. I have actually been rather lucky after it took me forever to get my first 20-S. I was a well struck PCGS 63BN you have seen in guess the grade. However, I got this one for <$30. The pictures make it look a bit weaker than it actually is. I would call it 62, BION.
My favorite by far is this one. I think they net graded it. My guess is that this coin has been wiped, but it is still a pretty coin and well struck.
There is nothing wrong with your cent except for the fact that it was struck on a defective planchet. The strike is actually very good and I compliment your good eye for the unusual.
I didn't really know where to post this, then remembered rlm posting about the characteristics of his 1920-S Lincoln. I found this one on eBay and wondered if anyone had ever seen anything like this: Item 110747766644 http://www.ebay.com/itm/Error-Bad-B...44?pt=Coins_US_Individual&hash=item19c914cf74 It didn't look like a lamination issue to me. I wonder if someone would have taken a saw to it, or maybe it's something I have just never seen.
It looks to be a former retained struck through where the material has either been removed or fallen out.
Are you saying that part of another coin came down and struck it, and then that piece came out? It's hard to tell from a picture, but it does appear to be about the width of another cent.
Struck through items can range from pieces of thread to bits of metal to grease and much more. These items are struck between the planchet and the press. These items can become inbedded and then fall out at a later date or in the case of the coin I posted, it was still present. Here's another example with is struck through a piece of wire: This one is struck through compressed debris which happened to fall out of a die:
If so, it's the biggest struck through I've ever seen. Looks like a nice a clean cut. I'd guess PMD but no theory to offer. The current auction bid of six cents seems about right. Lance.