How do you throw away a United States Flag? You don’t.
In honor of those who fought and died for the United States, and in honor of its symbol, we discuss the proper care due to the flag as defined in the law, and how to respectfully dispose of a worn flag.
U.S. Flag law is contained in Title 4, Sections 1-10 of the United States Code.
Because of the conflict with the First Amendment, Title 4 Sections 1-10 are entirely voluntary and are not enforceable by law. (Military and federal employees are bound in the course of their duties at least.)
USCODE-2011-title4-chap1