I have a 3 year old who is potty trained but still has accidents, and not all surfaces can be thrown in the washer. Case in point - your car's seat cannot be put in the washer. So, I have heard before that white vinegar added to your washload will get the urine scent out of clothes - and that is true, I have used it for about a couple of years now. A couple of days ago however, I had to get the scent out of something - so here's what I did, I used clean towels to soak up as much as possible, then I took my White
Vinegar and Water Cleaning Solution and spray and medium mist (enough to dampen the surface - more than a light mist, but not a soaking either) and I just left it there. It took a couple of hours to air dry but the urine scent was gone. The area does not smell like vinegar either. I mean if you stick your nose right up to the surface (I did just to check to make sure the urine odor was gone) you can get a faint vinegar smell. But it's very very faint, and only if your nose is stuck right up on it. Move 3 inches away, and you can't smell it at all.
I have used febreeze a lot for many household surfaces, and it works well, but urine and feces are tough odor and vinegar generally kills both odors well. This is very important if you have small children :)
*** I generally use a 1:10 white vinegar:water ratio for my home all purpose cleaning, and this same stuff is what I sprayed on the area. If you have pets it may take a higher concentration, or even straigt white vinegar spray. Let me know if you try this.***