28 CFR 540.25 - Change of address and forwarding of mail for inmates.
(b) Inmates are responsible for informing their correspondents of a change of address.
(c) Postage for mailing change of address cards is paid by the inmate.
(d) Except as provided in paragraphs (e) through (g) of this section, all mail received for a released or transferred inmate will be returned to the U.S. Postal Service for disposition in accordance with U.S. Postal Service regulations.
(g) Staff shall permit an inmate released temporarily on writ to elect either to have general correspondence held at the institution for a period not to exceed 30 days, or returned to the U.S. Postal Service for disposition.
(1) If the inmate refuses to make this election, staff at the institution shall document this refusal, and any reasons, in the inmate's central file. Staff shall return to the U.S. Postal Service all general correspondence received for such as inmate after the inmate's departure.
(2) If the inmate does not return from writ within the time indicated, staff shall return to the U.S. Postal Service all general correspondence being held for that inmate for disposition in accordance with postal regulations.