OK, obviously if a machine has only, well, been used in a home, it's clearly HUO.
But what if it's been used outside of a home environment, but still not routed? We have a Star Trek Pro here at our office that was purchased new, and it's only been here. It's within our security area, so a badge is required (i.e. only employees/contractors) to access it. It's been on free play its entire life. There's never been any alcohol or smoke near it, although I can't be certain about food/drink.
How would one describe this?