§ 601. Letters carried out of the mail
(a)
A letter may be carried out of the mails when—
(2)
the amount of postage which would have been charged on the letter if it had been sent by mail is paid by stamps, or postage meter stamps, on the envelope;
(b)
A letter may also be carried out of the mails when—
(1)
the amount paid for the private carriage of the letter is at least the amount equal to 6 times the rate then currently charged for the 1st ounce of a single-piece first class letter;
(3)
such carriage is within the scope of services described by regulations of the United States Postal Service (including, in particular, sections
310.1 and 320.2–320.8 of title 39 of the Code of Federal Regulations, as in effect on July 1, 2005) that purport to permit private carriage by suspension of the operation of this section (as then in effect).
(c)
Any regulations necessary to carry out this section shall be promulgated by the Postal Regulatory Commission.