Why don’t most people Toivel aluminum pans?
The laws regulating tevilas keilim (immersion of vessels and utensils in a mikvah) are based on the parameters of a vessel or utensil’s use—food preparation—and on its materials and construction. An exception to this rule would be a kli (vessel) that is disposed of after use—therefore, single-use containers or cutlery do not require immersion.
“Disposable” aluminum pans, although they are arguably meant to be single-use, are often reused several times. Strictly speaking, disposable pans that one plans to reuse would require tevilah before being used even once. Yet, we find that this is not the common custom. What is the halachic justification for not immersing them?
Original Design: The intention of the manufacturer is to produce a single-use pan, unrelated to how the consumer decides to (mis)use it. An item that is considered disposable at the time of its formation is not mekabel tum’ah (receptive to impurity). Some authorities extend this rule to obviate the need for tevilah of disposable items, although mainstream halachic standards generally differ for tum’ah and tevilah.
Objective Impermanence: Even if a disposable pan is used more than once, it can be argued that since it has a limited lifespan it should not be considered a kli altogether.
Rabbinic Say-so: Aluminum, being a fairly recent invention, is not one of the six metals that are mentioned in the Torah requiring tevilah. As such, some maintain that the immersion of aluminum utensils is mi’d’rabbaban (by rabbinic decree), allowing more room for leniency.
End-User Device: An aluminum pan is intended to be disposable—it is the consumer who may decide to use it multiple times. Therefore, the end-user, a Jew, can be considered to be the one who made it into a bona-fide kli. A kli created by a Jew does not require tevilah.
Decisions, Decisions: The nature of an aluminum pan’s construction demands that it be examined for viability every time it is reused. There is no overall or official decision to create a permanent kli, only a case-by-case decision, before or after, on its usability.
Redressed: Often, before an aluminum pan is used, it is lined with baking paper for health reasons, optimal baking or convenience. Since the food does not come into contact with the pan, this may exempt the user from immersing it.
Although none of these reasons on their own may suffice to exempt one from tevilas keilim of aluminum pans, the combination of all—or many—of the above are sufficient justification for allowing re-use without tevilah.