ויקרא, פרק ו׳, פסוק כ״א

Preparing the sin offering involves a unique transfer of holiness. As the sacred meat cooks, the walls of the vessel absorb its flavor, turning the pot itself into an object of holiness. This creates an immediate challenge. Once the strict time limit for eating the sacrifice expires, any remaining meat becomes forbidden and must be destroyed. If the flavor trapped in the walls of the pot remains, it too becomes forbidden, potentially ruining any future food cooked in it. To prevent this, the required treatment of the vessel depends on the material it is made from.

Earthenware, along with any similar porous material [מלבי״ם, תורה תמימה], must be broken. The concept of cooking in this context extends to any action that causes the vessel to absorb flavor, such as pouring boiling water into it [תורה תמימה, רש״ר הירש]. The reason for breaking the vessel is rooted in the nature of porous clay, which never fully releases the flavors it absorbs, making standard cleaning methods ineffective [רש״י, רבנו בחיי].

This requirement raises a question, as absorbed flavors typically become stale overnight, and stale flavors generally do not render a vessel forbidden. One explanation is that the meat becomes forbidden at the exact moment dawn breaks, which is the same moment the flavor is considered stale. Therefore, at the precise time of the prohibition, the flavor is still considered potent [מזרחי, לבוש האורה]. Another perspective argues that leftover sacrificial meat must be actively destroyed regardless of its taste. Since it is impossible to burn flavor trapped inside clay, breaking the pot is the only way to eliminate it [שפתי חכמים, דברי דוד]. A third approach suggests that sacrifices must be consumed in a manner of royalty and honor, meaning even a stale flavor would disqualify the offering [ריב״א, פרדס יוסף]. The breaking does not require completely shattering the pot; it only needs to be damaged enough to render it unusable, and this must take place within the holy courtyard [רבנו בחיי, רלב״ג].

Copper, which represents all metal vessels [חזקוני, מלבי״ם], follows a different rule. Because metal can expel what it absorbs, the vessel must be scoured and rinsed with water. Scouring involves polishing away grime and rust [רש״י, הכתב והקבלה], or specifically drawing out the absorbed broth [מלבי״ם]. The primary approach among commentators is that scouring is done with hot water to extract the flavor trapped inside, while rinsing is done with cold water on the outside [רבנו בחיי, תורה תמימה, ביאור יש״ר]. This process must be performed strictly with water and not with other liquids like wine [תורה תמימה, רלב״ג]. Furthermore, the cleaning does not need to happen immediately after every use. A pot may be used multiple times throughout the permitted eating period, and it is only cleaned at the very end before the flavor becomes forbidden [מלבי״ם, חזקוני].

Beyond the practical rules, the purification of these vessels mirrors the spiritual state of the person bringing the sin offering. A person whose sins are deeply ingrained and who struggles to abandon negative habits is compared to an earthen vessel that cannot release what it has absorbed. For such an individual, the only remedy is the breaking of their own pride and heart. Conversely, a person who sins unintentionally is compared to a metal vessel. Their flaws are merely on the surface, and they can be cleansed through the scouring and rinsing of Torah study and repentance, which purifies them both inside and out [כלי יקר, ש״ך].