I don't want to offer the easy/expensive fix but if it were mine I would toss it. Especially if you know that the urine is in the jute padding. You'll never get that out. Mice spread their pee and poo because they can't see in the dark and us it as a trail. You might get it to where you can't smell it but, you probably will on hot days or days running the heater. I hate that smell. No way I would do it.