[11-6-23] Priority Mail packaging provided by the USPS must be used only for Priority Mail. The mailer of any material mailed in USPS-provided Priority Mail packaging, regardless of how the packaging is reconfigured or how markings may be obliterated, is charged the appropriate Priority Mail price.
[1-22-23] When sealing a Flat Rate Envelope or Flat Rate Box, the container flaps must be able to close within the normal folds. Tape may be applied to the flaps and seams to reinforce the container, provided the design of the container is not enlarged by opening the sides and the container is not reconstructed in any way.
