Getting rid of the cat is like saying get rid of your children, sometimes she pisses me off(only the pee issue)...but this just recently happened. Before she would always use the litter box, never had any issues and we've had her for 10 years now. I used some alkaline, let it sit, than used some lovely cotton pads and skated around in them. I knew they were good for something!
Cotton pads - great for urine removal from your tiles.