Ten years ago I adopted a male kitten with a feral background. He was adopted into a…

Wow, it appears you’ve tried a great deal of things with this boy. You don’t mention how many litter boxes you have and I would suggest that you add another one and have at least two. Some cats prefer having a facility for urine and a different one for feces. There’s also a product called “Cat Attract” that can be added to your regular litter box substrate that works wonders with some cats.

This time of the year often prompts more spraying behavior simply because other cats outside that he hears and smells could be romancing each other. Does he have window-access where perhaps he sees other cats trespassing in his yard? If he doesn’t see them, that sometimes can help cut down on the spraying.

One of the best things to do is make sure you’re cleaning up all of his targets so no lingering aroma draws him back to re-baptize the spot. Invest in a black light (pet product stores will have these). Turn out the lights, and shine the light on the furniture or other areas he’s sprayed, and the urine will glow so you know where to clean. Use a product that actually neutralizes and eliminates the entire odor. It can’t just smell clean to YOU, it has to be cat-nose-proof. I have an article called “Out Darn Spot!” at my website http://www.shojai.com/articles-index.html

that lists several good products and how they work.