From experience! The baking soda trick won't work. The enzyme wash didn't work for me. The reason is the first day you have that is high in humidity (approx 65% & up)that stink is going to come up thru anything (like that) you put down. I don't know about sealing with shellac or maybe polyurethane, I think if I tried those, I surely would leave the carpet and all off for quite awhile to just make sure. AND also, did you know cat urine is fluorescent? Just borrow a blacklight from your teenage neighbor, or you could buy a blacklight bulb at your local wallyworld (or whatever you have)and then check your room, even if you can't smell it, you will most certainly see it if any is present. If I could afford to replace the strand I probably would just go that way- save myself all the headache!