18 U.S.C. § 1463 : US Code - Section 1463: Mailing indecent matter on wrappers or envelopes

Search 18 U.S.C. § 1463 : US Code - Section 1463: Mailing indecent matter on wrappers or envelopes

All matter otherwise mailable by law, upon the envelope or
outside cover or wrapper of which, and all postal cards upon which,
any delineations, epithets, terms, or language of an indecent,
lewd, lascivious, or obscene character are written or printed or
otherwise impressed or apparent, are nonmailable matter, and shall
not be conveyed in the mails nor delivered from any post office nor
by any letter carrier, and shall be withdrawn from the mails under
such regulations as the Postal Service shall prescribe.
Whoever knowingly deposits for mailing or delivery, anything
declared by this section to be nonmailable matter, or knowingly
takes the same from the mails for the purpose of circulating or
disposing of or aiding in the circulation or disposition of the
same, shall be fined under this title or imprisoned not more than
five years, or both.