It is a commandment to kill the residents of a city in which the Jews have switched to idolatry, including the minority which have not switched; their property is to be confiscated and burned. It is written in the Torah, “You shall smite the inhabitants of that city with the edge of the sword, destroying it utterly and all that is therein, and the cattle thereof, with the edge of the sword. And you shall gather all the spoil of it into the midst of [the city’s] street, and you shall burn the city with fire, and all the spoil thereof, every bit, for the Lord your G-d. It shall be a heap for ever; it shall not be built again” (Deuteronomy 13:16).
The sages of the Mishnah and the Talmud discussed this issue, a city whose Jewish residents became idolaters (ir hanidachat) at length. The sages ruled that the property of those of the city’s residents who had not converted to idolatry must be burned, but their attire and clothing need not be. One sage, Rav Yosef, asked about a wig found in a closet and not on a woman’s head. What are the issues under debate? On one hand the wig in the closet should be seen as property and so burned. On the other hand, since it was frequently worn, it is attire and does not require burning. (This question was not resolved in the Talmud. It is important to note that the laws of a city whose Jewish residents converted to a different religion are no longer relevant.)
(Babylonian Talmud, Tractate Sanhedrin 112a)