Jerry more or less hit the nail on the head there.
I've bought from Shelly before when she first started listing all these pennies and alas the coins were cleaned, I got in touch and explained that they weren't advertised as such and she told me she didn't know if a coin was cleaned or not, and I returned them for a full refund, including postage. I wouldn't buy from her again, but in her defence the return was trouble free, albeit a bit intense.