In addition to the correct postage, the mailer must pay the certificate of mailing fee for each article on PS Form 3817, Certificate of Mailing. For each duplicate copy of PS Form 3817 requested after mailing (see 312.2), the mailer must pay a separate fee. See Notice 123, Price List.
To receive a reduced fee when mailing three or more pieces, the mailer may optionally use PS Form 3877, Firm Mailing Book for Accountable Mail. The mailer must pay the certificate of mailing fee with a permit imprint or by affixing ordinary stamps, precanceled stamps, or metered stamps to PS Form 3877. For a separate fee, the mailer may request a duplicate copy of PS Form 3877 after mailing (see 312.2). See Notice 123, Price List, for all applicable fees.
The mailer must make all entries on firm sheets by typewriter, ink, or ballpoint pen. The mailer may also use computer-generated firm sheets that contain the same information as PS Form 3877. The mailer must obliterate all unused portions of the addressee column by drawing a diagonal line through them. The mailer and accepting employee must initial any alterations to the firm sheets. The sheets of the books become the sender’s receipts.
For bulk mailings paid with ordinary stamps or meter stamps, the mailer may optionally use PS Form 3606, Certificate of Bulk Mailing — however, the mailer cannot use PS Form 3606 for a bulk mailing paid with a permit imprint. The mailer must affix stamps or meter stamps to the form to pay the bulk certificate of mailing fees. See Notice 123, Price List.
PS Form 3606 is provided only for a mailing of identical pieces under 312.1. It only verifies the total number of articles mailed, and it must not be used as an itemized list.