Joe- I hope you didn't think I was criticizing your catbox cleaning. I agree- cat pee is much worse than kid pee- more ammonia! I've had several cats, and esp the Siamese were very persnickity about the litter box. They would sternly announce their demand for the maid immediately upon vacating the box. Unfortunately the maid was very lazy, and thought once or twice a day was enough. I hope it was just an unhappy accident. The vinegar smell will dissipate soon. Once the blocks are totally dry maybe you can try adding a used fabric softener sheet to the box if there's a scent that doesn't bother you. I've been trying to remember the Dr Seuss story about the spot that stained the house, tub, etc. Each remedy had worse consequences!