Heavily worn out and not wind or water tight. Best for scrap metal or parts. Many dealers fix and sell as wind and water tight). 

A container with heavy rust, heavy dents, and doors can be tough to open, could have a weak floor and small leaks) many dealers will try to tell you this is cargo worthy, these containers could not be certified as cargo worthy due to some type of issue with the container.

Sometimes called Grade A, these containers have doors that open properly with light to medium rust and dents with plenty of life left in them. 

One trip or new these containers have been loaded overseas with cargo, unloaded here and then immediately sold. They look like new containers and could have small dents or scratches