John Gill Commentary 2 Kings 23:24

"Moreover them that had familiar spirits, and the wizards, and the teraphim, and the idols, and all the abominations that were seen in the land of Judah and in Jerusalem, did Josiah put away, that he might confirm the words of the law which were written in the book that Hilkiah the priest found in the house of Jehovah." — 2 Kings 23:24 (ASV)

Moreover, the workers with familiar spirits, and the wizards ,
&c.] Who were not to be allowed among the Israelites, (Deuteronomy 18:10Deuteronomy 18:11)

and the images; or teraphim: and the idols, and all the abominations ;
which were worshipped by the Heathens, and introduced among the Jews, and forbidden by the word of God:

that were spied in the land of Judah, and in Jerusalem, did Josiah put
away ;
for which, it seems, diligent search was made, and wherever they were discovered were removed:

that he might perform the words of the law, which were written in the
book that Hilkiah the priest found in the house of the Lord ;
both with respect to witchcraft and idolatry, see (Leviticus 20:27) (Exodus 20:4Exodus 20:5) (23:24) .