USCIS has rescinded an earlier notice from July 23, 2007 discontinuing the use of "prepaid mailers."

USCIS will continue to accept prepaid mailers or envelopes from courier service which meet the following criteria: Express and Priority mail (including Fed Ex, DHL, or UPS) with appropriate postage with prepaid shipping label on the package, already paid by person who sends it, e.g., Fed Ex "Expanded Billable Stamp." or DHL "Easy Return Label."