Rav Menashe Klein On Reusing Stamps And The Chofetz Chaim Ripping Up A Stamp
When a letter is mailed, the post office stamps the postage stamp invalidating for further use. What happens if you receive a letter where the postal clerk missed the mark and he inadvertently stamped the envelope instead of the stamp? May you remove the stamp and reuse it?
Rav Menashe Klein in Mishna Halachos (6:288) says that stamp is a way for the government to charge you for the service they provide. If the clerk made a mistake there are two halachos that must be considered. First is the Halacha of Hashavas Aveida. If the government were a private person than the halachos of Hashavas Aveidah to a goy would apply. Returning an aveidah to a goy is allowed if it will make a Kiddush Hashem and is required if by not doing so you will cause a Chillul Hashem.
However since the service provider in this case is the government, the Halachos of Dina DiMalchusa Dina apply and one is obligated to honor the law of the land. While there are many halachos describing exactly which governments are considered Dina DiMalchusa, he generally says that a country where laws are applied equally to all citizens with no regard for race or religion is a government that must be honored Halachicly. Therefore the stamp may not be reused because the law requires you to pay a fee if you send your letter through the postal system.
He also says that the famous story of the Chofetz Chaim who ripped up a stamp when he found someone who would personally deliver his letter, was not grounded in Halacha. You don't have an obligation to pay the government money when your friend delivers your letter. The Chofetz Chaim ripped the stamp because in his great kedusha he wanted to make a Kiddush Hashem.
Disclaimer: We try to convey the Tshuva to the best of our ability. We admit that our understanding may not be accurate. Please also understand that this Tshuva may not be the final word on this topic. One should consult a Rav before drawing any conclusions.