BerniceC: the best stuff I ever used to get rid of animal pee (especially dry as it's more difficult to get rid of) was a special liquid from the vets. I can't remember what it was called but it has special enzymes in it which break down the smell & also stop the animal going back to the same spot to re-pee there!
It wasn't too expensive either!
So it might be just as well to try your vets to see if they sell anything like that........