Beware that all "pet" odor removers are not the same. One that I know for a fact works (because I've used it for YEARS) is Nature's Miracle. The best thing is it has a money-back guarantee. You can buy it by the gallon or in spray bottles at any pet store.
Another thing I love about it is that it's not just for pet stains. It works on vomit, mattress stains, blood...basically any stain originating from humans or animals. You can use it on laundry, furniture, carpet, etc. I even washed an entire floor with it...letting it soak into the cracks between tiles, when cleaning a house after 10 cats moved out. That place had stunk to high heaven for YEARS...there was cat barf, diarrhea and pee everywhere. Nature's Miracle got rid of it all!
It's an enzyme, so it eats the *source* of the stain; it doesn't mask it with a scent. I've heard Bac-Out works well too, but I haven't used it personally.