Prepared steel/iron scrap must be one quarter inch thick or more, with material no larger than 2 feet by 5 feet in size. It may not include materials such as non-ferrous metals (copper, aluminum, brass, etc.).

Unprepared steel/iron scrap can include materials larger in size than prepared materials.  Typically, materials should stay within the 6 feet by 20 feet range.  These materials can contain non-ferrous attachments such as copper, aluminum, and brass. 

Prepared steel has more value than unprepared, and sells for more money.  One should consider labor costs/time when preparing iron/steel versus selling unprepared.