Q. May one kasher plastic bowls and utensils for Pesach?
A. Rav Moshe Feinstein zt”l (Igros Moshe Orach Chaim II: 92) was asked whether it is permissible to kasher synthetic materials for Pesach. He writes that the Torah sets forth guidelines for kashering metal, wood and clay, but does not discuss new materials that were recently developed. Since we do not have any clear guidelines from the Torah or early poskim as to what they might have held regarding these new materials, we should not permit kashering them.
However, many other poskim including Minchas Yitzchak (3:67), Chelkas Yaakov (Yoreh Deah 45), Tzitz Eliezer (4:6) and Rav Ovadya Yosef zt”l (Chazon Ovadya, Hilchos Pesach) were lenient, provided that the plastic will not melt or get ruined from the kashering process. However, if the plastic has scratches or cracks, it cannot be kashered.
Many in America have the minhag to follow Igros Moshe and not to kasher plastic. However, if one does not know if that is their minhag, it is the position of the OU poskim that one may be lenient if there is a need.
This column, from the OU Kosher Halacha Yomis, is dedicated in memory of Rav Chaim Yisroel ben Reb Dov HaLevy Belsky, zt’l, Senior OU Kosher Halachic Consultant (1987-2016)