VATICAN CITY — The Vatican’s saint-making office has updated its rules governing the use of relics for would-be saints, issuing detailed new guidelines Saturday that govern how body parts and cremated remains are to be obtained, transferred and protected for eventual veneration.

The instructions explicitly rule out selling the hair strands, hands, teeth and other body parts of saints that often fetch high prices in online auctions. They also prohibit the use of relics in sacrilegious rituals and warn that the church may have to obtain consent from surviving family members before unearthing the remains of candidates for sainthood.

Bodily relics are an important part of Catholic tradition, since the body is considered to be the “instrument” of the person’s saintliness. Beatification and canonization Masses often feature the relic being ceremoniously brought to the altar in an elaborate display case and allowing the faithful to publicly venerate the new blessed or saint for the first time.

Officials said the new guidelines were necessary given some obstacles that had arisen since the rules were last revised in 2007, particularly when surviving relatives and church officials disagreed. One current case before a U.S. appeals court concerns a battle over the remains of Fulton Sheen, an American archbishop known for his revolutionary radio and television preaching in the 1950s and 1960s.

Sheen’s niece went to court to force the archdiocese of New York to transfer Sheen’s body from the crypt of St. Patrick’s Cathedral to Peoria, Illinois, where Sheen was born, ordained a priest and where his sainthood cause has been launched by Peoria’s bishop.