פירוש על במדבר 31:23

כל דבר אשר יבא באש ANYTHING THAT COMES ON THE FIRE, to boil something in it,

EVERY THING THAT MAY COME INTO THE FIRE YE SHALL PASS THROUGH THE FIRE AND IT SHALL BE CLEAN. A vessel which touched a human corpse or dead animal does not become purified by fire, since the immersion mentioned in the Torah is always in water. Therefore our Rabbis had to explain⁹⁷Abodah Zarah 75b. that this purification [mentioned here by Scripture] refers to remove from them [the traces of] the forbidden foods which they had absorbed whilst they were in the possession of the non-Jews. This is the true [explanation] without any doubt.

וטהר, it will have become decontaminated from the negative vibes attached to it as residue of idolaters.