Thanks guys. Last night, after I got home (and before I read your responses this morning) I cleaned up the poop, sprayed it with "Nature's Miracle", laid down newspaper and then blocked off the little nook where it was. After I cleaned up that mess, I tackled the litter boxes where both Maya and Kimi came in and used them right in front of me (anyone else have cats that love to "go" the second you start scooping?). Anyway instead of getting annoyed, I praised both girls for going potty in the box.

That was at about 3pm yesterday and as of 7am this morning, no new accidents - ANYWHERE in the house! If something happens and we do go back to kitty "treats" where they're not supposed to be, I'll try what catnapper suggested... I'm keeping my fingers crossed that this is it though!!!