Genesis 35:2

And Jakob said to the men of his house, and to all who were with him, Put away the idols of the peoples which are among you which you took from the temple* of Shekem, and purify you from the uncleannesses of the slain whom you have and change your raiment.

1 Remove all of your strange gods. Heaven that a prophet should lie with a woman who worshiped foreign gods! And the explanation for this is as we find in Parashat Vayelech (Deuteronomy 31).

2 purify yourselves. that you should wash your body

3 and change your clothes. From this source we learn that is incumbent upon any Israelite when he goes to pray in a fixed place to have a clean body and clean clothes.

אלוהי הנכר, which they had looted from Shechem.

הסירו את אלוהי הנכר, which you have taken from Shechem. Even though the adherents of these idols had already disowned them, (the surviving females of the city of Shechem), and we know from Avodah Zarah 43, and 52 that such items are subsequently permitted to Jews, Yaakov commanded his household to get rid of them before proceeding to Bet El. He wanted all his people to mentally completely dissociate themselves from anything connected wit items formerly used in idolatrous pursuits.

אל ביתו, to his children.

ואל כל אשר לו, to his men and maidservants.

הסירו את אלוהי הנכר, the silver and gold the sons of Yaakov had looted from Shechem had idolatrous images engraved upon them, as had the various pieces of jewelry they had taken with them from there. Even though Yaakov’s sons had not taken these items in order to worship them but in order to melt them down and to put them to other uses, i.e. to use the melted down gold and silver, [something halachically acceptable as the idolatrous nature of these artifacts had been nullified through the melt down, Ed.] Yaakov did not want his children or household to benefit from anything which had once served idolatrous purposes although it was no longer recognisable as something that had once served such a purpose. Moses is on record as expressing similar sentiments when he said (Deuteronomy 7,25) “do not covet the silver or gold which was upon them.” (after the idols themselves had already been destroyed) He repeated this sentiment even more strongly in Deuteronomy 13,18 when he said “no part of the banned property may adhere to your hand, etc.” [these injunctions were especially called for after the Israelites had not only been allowed to loot the property of the former owners, but other Torah legislation such as even the eating of pig had been temporarily suspended during the years when the conquered the land of Canaan and had not yet settled there and received their tribal heritage. Ed.]

והטהרו; they needed to purify themselves as contact with idolatrous objects confers ritual impurity on the person who had been in touch with it.

והחליפו שמלותיכם, your garments too have become contaminated by the same ritual impurity so that you have to put on others. Alternatively, what is meant are the garments of the people of Shechem which were part of the loot.