https://www.btstories.com/josiahs-reforms/

King Josiah and the nation of Judah renewed their commitment to the Laws of God. The king then took all the false altars out of the Temple and had them burned. The people also went throughout Jerusalem and destroyed all the idols that were in the city.

Once that was done, the king personally went throughout the land of Judah and oversaw the destruction of idol worship in all the cities. Next he went throughout the land of Israel and destroyed all the idols and altars that were there. When he found a major pagan spot, he desecrated the altar so the people would never use it again.