Publication 2 - Packaging for Mailing - Postal Explorer - USPS.com

Packaging Adequacy1-4.3.11-4 Acceptability1-4.1 GeneralBesides load type, packaging acceptability is one of the principal standards ofmailability. A container must not be packed in a way that might cause or allowits contents to injure Postal Service employees or to damage other mail ormail processing equipment. Fragile items must be packed to withstand mailprocessing and transportation. Heavy items must be braced and cushioned toprevent damage to other mail.Items described in 1-4.2 through 1-4.5 often cause problems whenimproperly packaged. Requests for exceptions to the requirements in thissection must be made to a rates and classification service center (RCSC)(see Appendix B for addresses).1-4.2 StationeryStationery items often become loose during mail processing. Problems arecaused by unrestrained, concentrated, or shiftingcontents and by inadequate internal packaging,containers, closures, and reinforcements.Stationery items that are thicker than 1 inch orheavier than 1 pound may not be mailed in letter-style envelopes.These items must be unitized by tying or banding them or by partitioningtight containers to prevent shifting.1-4.3 Liquids1-4.3.1 ContainersLiquids can damage or destroy other mail and mail processingequipment. Generally, containers of liquid with only friction-topclosures (push-down type) are not acceptable. Screw-on caps,soldered tops, clips, or other means are necessary for secureclosing.Glass and other breakable containers holding more than4 fluid ounces must be cushioned with a material that canreadily absorb any leakage. These primary containers mustbe placed and packed inside sealed, leak-proof containers. If acontainer holds more than 32 fluid ounces, it is not acceptable for mailingunless cushioned as described above and packed within another sealed,leak-proof container such as a can or plastic bag. The outer mailing containermust be strong enough to protect the contents, must be marked “LIQUID,” andshould display orientation markings (i.e., up arrows) that indicate the uprightposition of the parcel.Publication 2, January 20023