Permission sure -But any container with only metal I don't even bother to ask . It has to be a mix and when that type of construction goes down you have all types of stuff besides metal so it's very clear
I had a great run on a container from a conversion from circuit city to a price right supermarket , I had permission copper wire SS AL Short Mix It was like a candy shop for me They were tossing out heavy steel doors also . I wish that lasted forever , sadly it one day is completed