OH MY GOD. THANK YOU FOR THIS THREAD. (Please excuz teh interwebz capz).
I have had many issues with inappropriate elimination from Nitro, which may, in part, be linked to me trying to get him trained on the CitiKitty. I've lost a bed over this and have been sleeping on the couch for nearly two months because he decided to eliminate one too many times on my mattress and in every other corner of my bedroom.
I ordered the "Litter Attractant" (just the herbs) from Amazon, got them in this morning, and despite my belief that I had already gotten Nitro to use the toilet, I spread only a few drops on top of the litter, and he immediately hopped on and went for it! I know this is too soon to call victory, but you may have just literally saved my back!