43. It is customary nowadays not to rely on kashering a chametz oven used all year long. Kashering it properly relies on many lenient opinions, and it does not reach the heat level of libun chamur. Therefore, it is proper for one to only use a designated Pesach oven.
44. Self-cleaning oven. Many use ovens with a self-cleaning feature that can get to 500 °C, considering that libun chamur. Therefore, after cleaning it thoroughly inside and out and making sure not to use it with chametz for 24 hours, they run the self-clean and rely on that to kasher it for Pesach. They have what to rely on.
45. Nevertheless, there are those who are doubtful about this since there are metal parts of the oven that are not in the interior space and that do not undergo proper libun. They are concerned about the rule that states that metal which got partially heated can absorb from a different part of the metal absorbing chometz (מילתא דשכיחא הגעלת כלים סי' ה ). Also, they are worried that the glass oven door and rubber parts of the oven do not get kashered.
