Certificates of mailing were available on fourth class parcels only until July 1, 1929, when it became available on all classes of mail. Form 2965 specifically stated it was for parcel post use even though, by the time this certificate was issued, Form 3817 could be used for any class.

Form 3817, used to certify the mailing of on piece of ordinary mail to Mexico. The one-cent certificate rate ran from September 1, 1915 until February 1, 1954.

At some point the same certificates of mailing were also available on the backs of postcards so they could be mailed to a third party.

Certificates of mailing to UPU countries were only available for parcel post packages from May 26, 1932 until January 1, 1934, when they became available for all ordinary mail. The fee was one cent from May 26, 1932 until February 1, 1954.

A certificate of mailing form for packages sent to a PUAS country.

This form provides a certificate of mailing for a small number of items, but was used here to certify mailing of only one.