So I built this thinline for a friend last year, and her cat unfortunately peed on the gig bag it was in, and the smell seems to have sunk into the neck pretty thoroughly (i.e., airing it out isn't working). There are no visible stains... just the smell... The neck is walnut, rosewood fingerboard, Minwax tung oil finish on the walnut. Is there some tried and true method for removing a cat urine stench?? Do I need to refinish this neck?