Preservation of product can be many things, but essentially it's just about what you do to protect your product from deterioration prior to delivery to the customer. Some bulk and other metals may have a protective coating of a rust inhibitor and/or may be packaged in (sometimes individually wrapped in) a protective, chemically treated paper. Some products need little or no 'special treatment'. Can be affected by storage conditions - for some products, if you keep product in cool, dry areas, no 'special protection' may be needed. Preservation methods may or may not be product specific.
If you want to cite more details of your scenario I'll address it in more detail.
Group? What say ye?