Packaging Media Mail should be done using the appropriate method. Media pieces can be wrapped using your own packaging materials. USPS sells packaging materials, but typically they are more expensive there than elsewhere.
Completely cover any fragile pieces such as antique books using bubble wrapping. Soft cover books will usually do best when placed in boxes or a stiff envelope. Remove all personal papers, letters, and other non media pages that might be stored in the books or cases.
Make sure to label the packaging with “Media Mail” on the front. Do not seal any of the packaging until you’ve reached the post office. Since Media Mail is subject to search due to the discounted pricing, postal workers may be required to examine the contents of your package.
Make sure to follow the packaging restrictions about the size and weight. Media Mail packages are limited to 70 lbs in weight and 108 inches in thickness.