18 U.S.C. § 1720 — Canceled stamps and envelopes

Whoever uses or attempts to use in payment of postage, any canceled postage stamp, whether the same has been used or not, or removes, attempts to remove, or assists in removing, the canceling or defacing marks from any postage stamp, or the superscription from any stamped envelope, or postal card, that has once been used in payment of postage, with the intent to use the same for a like purpose, or to sell or offer to sell the same, or knowingly possesses any such postage stamp, stamped envelope, or postal card, with intent to use the same or knowingly sells or offers to sell any such postage stamp, stamped envelope, or postal card, or uses or attempts to use the same in payment of postage; or

Whoever unlawfully and willfully removes from any mail matter any stamp attached thereto in payment of postage; or

Whoever knowingly uses in payment of postage, any postage stamp, postal card, or stamped envelope, issued in pursuance of law, which has already been used for a like purpose—

Shall be fined under this title or imprisoned not more than one year, or both; but if he is a person employed in the Postal Service^*, he shall be fined under this title or imprisoned not more than three years, or both.