Hagalah with steam

Hi,

One cannot kasher via hagalah with steam alone, regardless of its heat, since it is not clear that the steam will cause absorbed taste to be extruded. However, where the steam comes from water at a high boil, and it causes significant quantities of water to develop on the surface, that suffices.

(Rav Moshe Feinstein, Igrot Moshe Yoreh Deah 1:60)

Have a great day,
Mordechai

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

Kashering rubber

Hi,

One may kasher wood-based rubber with "hagalah", just as one may kasher [smooth] wood with that method. However, this will not necessarily apply to synthetic rubber.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 2:92)

Gmar tov,
Mordechai