Guess The PCGS Grade 1866 $1

Yes PCGS probably knocked it down due to the toning. Their web site indicates a coin can be upgraded or downgraded several levels due to eye appeal:

http://www.pcgs.com/eyeappeal.html

IMO the dark toning doesn't look bad on the reverse.

Perhaps you could send it to NCS and see if they are able to remove something. I am sure they can't do anything about the toning but they could sure do something about the other issues.

Maybe it's time for a resubmit?

As far as I know, PCGS doesn't have a conservation service. Perhaps during a show where NGC sets up shop, you could submit it to NCS. Not sure if they come to the Canadian shows often.

That's a pretty reasonable offer at the grade. PCGS will_not take a Mint State coin below MS60 based on eye appeal, so this coin has seen circulation. Say what you will about them, but PCGS rarely misses Circulated vs. Uncirculated when they give a grade as low as AU53. AU58, I'll argue, but not 53.

Seated dollars are not uncommon with toning this dark (it's not crud, it's toning), and they're less likely to lose drastic eye-appeal points - in no way exceeding two Sheldon Scale points anyways - than other issues with similar toning.

Although NCS can remove toning from a coin, it's an iffy proposition indeed to have toning removed from a circulated coin. I will not dip a circulated coin, under any circumstances. If you do have them conserve, and it makes it into an NGC slab, you're looking at roughly a 5-point reduction in value over PCGS-slabbed prices, anyways, so you'll lose the value of grade gained.

I was thinking AU 58. I still can't figure out how the TPG's handle the eye appeal factor.