Avodah Zarah 75b: If a pot was used to cook treif, the Torah forbade it only within 24 hours; afterwards it imparts a bad taste to the food. If so, let it be permitted! – The Sages banned it lest one come to use a pot within 24 hours.
עבודה זרה עה ע”ב: אמר רב חייא בריה דרב הונא: לא אסרה תורה אלא קדירה בת יומא, דלאו נותן טעם לפגם הוא. מכאן ואילך לישתריִ גזירה קדירה שאינה בת יומא משום קדירה בת יומא.
In the 1980’s, Rabbi Yaakov Neuberger served as rav of the student community at Albert Einstein College of Medicine. One day, he was approached by a married student with a halachic question. “My wife and I are becoming religious, and we kashered our whole kitchen. However we have one very nice ceramic pot, and I’ve heard that you can’t kasher ceramic. Is there any room for leniency?”
Rabbi Neuberger’s first instinct was to say no, but he sensed that the question was highly important to the young man, and so he told him, “Let me get back to you.” He went and presented the shailah to Rabbi Dovid Lifshitz, who said, “Tell him he can be lenient and rely on the Baal Ha’Itur.” The Baal Ha’Itur writes that according to the Yerushalmi an earthenware vessel may be kashered by performing hagalah three times after it has been left unused for 24 hours. This means the utensil is submerged into three different pots of boiling water. The Rashba writes that this leniency of the Yerushalmi applies only in very limited cases, such as when kashering from “bishul akum.” The Shulchan Aruch (YD 113:16) follows this ruling of the Rashba. However, Rav Lifshitz relied on the Baal Ha’Itur for this young couple’s real treif pot because he felt it was important to be lenient on people just taking the plunge to a frum lifestyle.
Many years later, Rabbi Neuberger happened to meet the man again. He was happy to hear that the man had spent many years learning Torah and now had several kids attending yeshiva. The man confided, “Back then, when I came to you, my wife was ready to go kosher but she wasn’t as motivated as I was. She found the process very difficult. When we thought we would have to throw out that ceramic pot, it was the last straw for her. Had you not found a leniency, I’m afraid we wouldn’t be where we are today.”
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