Special packaging involved. No previously used packaging. All new material. No scotch tape, masking tape, or waxed or plastic tape of any kind. Must be able to hold ink.
All seams are bulls-eye stamped at receiving post office.
Only paper tape should be used. No padded of jiffy envelopes as they are too easy to get into and take contents. No address labels . Address should be written directly on package in something that will not run if it gets wet. In addition to these packaging requirements everyone who handles this piece of mail is required to sign for it.