Wrapping matter not charged with first class postage

§ 4058. Wrapping matter not charged with first class postage (a) The Postmaster General may prescribe the manner of wrapping and securing mail not charged with first class postage so that the contents of the mail may be easily examined. He shall charge the first class rate of postage on all matter which cannot be examined easily. (b) To ascertain whether the proper rate of postage has been paid, postmasters may examine second class mail and remove the wrappers and envelopes from other mail not bearing first class postage if it can be done without destroying them.