LMAO.... this was my big problem YESTERDAY in my daughters bedroom! We have a new puppy who seems to have found where our dog from 9 years ago would pee.... we have changed the carpet but I am guessing it is in the underlament or something?!?!
Saturday I was at the dollar store and found Rose Scented Oil... you can get Essential Oils from lots of places (I got lucky to find them there)! I mixed about 15 drops in a small box of baking soda and mixed up really well! I put it on the carpet and waited about 2 hours before vacuuming it up. Her room smells awesome now! I even had company mention it today and ask what I was using for air freshener in there since it smelled so nice!
I also put more on the areas I know she has peed.... I am hoping it takes away the odor so she does not go there again! If not I will have to find something to stop that from happening!
Good luck and blessings to you!