Animal pee: Cats don't usually urinate on top of things - they like to do it on the ground or floor. A visiting Tom cat might spray on the side of a box - and that is pretty pungent. Urine on the top of a box is more likely dribbled down from a nest of rats or maybe a possum if they are in the locality. More likely something wild than something tame. But probably a deodorant for cat pee will be as good as any.

Personally, I see the value of boxes as determined by the level of Obsessive Compulsive Disorder among collectors. A vintage computer is not Star Wars merchandise. It should have a history worth preserving, not just a virginal state. (same with people :O ).

Rick