Kashering aluminum

Hi,

Some contend that aluminum utensils may include other materials which cannot be kashered with the 'hagalah' method used normally for metals. However, since we wait 24 hours before kashering so that the need to kasher is rabbinic, and since these utensils may not absorb at all, there is no concern. One may employ hagalah.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 3:58)

Have a great day,
Mordechai