For those of you doing save the date magnets, read these important post office guidelines:
Mailing refrigerator-type (flexible) magnets is often a source of concern because their design can disrupt or interfere with the efficiency of mail processing equipment.
Over the last 4 years the Postal Service Engineering has conducted extensive testing that has identified guidelines for mailing refrigerator-type magnets. These efforts along with the technical advancement in our processing equipment, now allow some greater flexibility in accepting certain magnets.
The following guidelines should be used when preparing magnetic mailpieces containing magnets:
1) Refrigerator-style magnets may be mailed at First-Class Mail and Standard Mail machinable or nonmachinable letter or nonletter rates, pending the applicable standards.
2) The maximum size of the magnet cannot exceed 4 1/4 inches in height and 6 inches in length.
3) The magnetic side must face the reverse (nonaddress) side of the mailpiece, whether prepared as card-style or enclosed in an envelope.
4) The magnet must be right-justified (leading edge) on the mailpiece. If the magnet is enclosed in an envelope it must be secured, right-justified inside the envelope.
5) Magnets prepared as card-style mailpieces must pay the appropriate letter-size rates. These card-style mailpieces are often enclosed in some type of plastic material that can make the mailpiece subject to the nonmachinable surcharge.