During Pesaḥ, it is not permitted to use the same cooking utensils or tableware that was used year-round for ḥameṣ. It is customary and most recommendable to have a separate set of cookware and tableware for Pesaḥ. If this is not possible, one can still use the year round utensils after a process known as hag'ala, which is a kind of sterilization. The rational of the hag'ala is that the ḥameṣ absorbed in the walls of any utensil will be expelled when that utensil is exposed to the same circumstances in which the absorption occurred in the first place (kebol'o kakh polto).
Absorption will take place only at high temperatures, thus, if a utensil was used only for cold food, it could be used during Pesaḥ after thoroughly cleaning it, without any further hag'ala.
Some examples of hag'ala:
Metal: Tableware like forks, spoons or knives have to be thoroughly cleaned and then immersed in a pot of boiling water. Afterwards, they need to be washed with cold water and then they can be used for Pesaḥ. Hot water opens the pores of the utensils, allowing the expulsion of the absorbed ḥameṣ. The cold water closes the pores again.
Glass: According to the Sephardic Minhag, glass utensils like cups or plates used throughout the year for ḥameṣ should be thoroughly washed and they can then be used for Pesaḥ without any further hag'ala. Glass utensils do not absorb anything thru their pores and therefore they do no expel any substance thru them. This is applicable even when the glass utensils are used at high temperatures. It should be noticed that this Halakha is radically different for the Ashkenazi custom.
Porcelain ( kele ḥeres): Ceramic, pottery or porcelain china and tableware that we use throughout the year for ḥameṣ are not suitable for Pesaḥ. In other words, they are an exception because hag'ala cannot sterilize them completely. Therefore year round porcelain or ceramic utensils should not be used for Pesaḥ.
Click HERE to obtain very important information on rice types and brands for PESAH 2013
In this document I quote verbatim the information I got from Mr. Shmuel and Mrs. Mojgan Liviem, as per Rabbi Eliyahu Ben Hayim, and the information published by Rabbi Yehuda Boroosan, regarding the use of rice for Pesah 2013.
