Dec7Written by:John (Host)
12/7/2007 4:27 PM 
The post office has made some adjustments to the mailing requirements for magnets. Some of the more relevant requirements are:
Both automation letters & flats:
- Minimum of 10 poles per linear inch.
- Magnets may not exceed 1/32 inch in thickness.
- The magnetic surface may face either the address or the nonaddress side.
Automation Letters:
- The magnetic surface may not exceed 26 square inches (length times height).
- Enclosed magnets must be affixed to the contents, wrapped within the contents to prevent excess shifting, or fill the mailpiece with no more than 1/2 inch clearance between the left and right edges of the magnet and the mailpiece edges.
- Magnets permanently attached to, or prepared as, an integral part of unfolded cardstock pieces should be located on the leading edge of the mailpiece.
Flats:
- Magnets must be enclosed in the flat-size mailpiece and either must be affixed to the contents, wrapped within the contents to prevent excess shifting, or fill the envelope with no more than 1/2 inch clearance between the left and right edges of the magnet and the mailpiece edges.
Sections excerpted from: Page 5 of Postal Bulletin 22221 for more detailed information, follow the link to the PDF.