A situation once arose where a person hosted a large number of guests on Shabbat and he needed more dishes. He had some brand new dishes stocked away, and he wanted to use them, but he realized that they had never been immersed. Halacha forbids using new utensils purchased from a gentile before immersing them, and thus he needed to immerse these dishes. (There is a common misconception that new utensils may be used once without immersion, but this is not correct.) Is it permissible to perform the immersion on Shabbat? Assuming there is no issue concerning carrying the utensils in a public domain – for example, one has a Mikveh in his home, or there is a valid Erub – may one immerse a new utensil in a Mikveh on Shabbat?
The Shulhan Aruch (Orah Haim 323:7; listen to audio recording for precise citation) writes that it is permissible to immerse a new utensil on Shabbat, but then adds "Ve’yesh Oserim" – "There are those who forbid it." This second view cited by the Shulhan Aruch is that of the Rif (Rabbi Yishak of Fez, Morocco, 1013-1103), who writes (in Masechet Besa) that immersing a new utensil resembles "Boneh" (building). A utensil before immersion is unfit for use, and by immersing it one renders it usable. Immersion thus constitutes "Tikkun Mana," fixing a utensil, which is forbidden on Shabbat by virtue of the prohibition of "Boneh."
Generally speaking, when the Shuhan Aruch issues a ruling and then notes that others disagree ("Stam Va’yesh"), he sides with the first view. As such, in this case, we would think that the Shulhan Aruch allows immersing new utensils on Shabbat. However, immediately after recording these two views, the Shulhan Aruch adds that a God-fearing person should avoid this issue by giving the utensil as a gift to a non-Jew and then "borrowing" it. For example, he can bring it to a housekeeper or neighbor and tell the gentile that he is giving the utensil to him or her as a gift, so it now becomes that person’s utensil. After the non-Jew takes hold of the utensil to formally acquire ownership, the Jew can then ask to borrow the utensil, and thereupon use it without first immersing it, since utensils borrowed from a non-Jew do not require immersion before use. Although Halacha generally does not allow giving or receiving gifts on Shabbat, for the purpose of a Misva it is permitted, and thus for the sake of avoiding the need to immerse a utensil one may give the utensil as a gift to a non-Jew. As a rule, we do not encourage employing this strategy to avoid the obligation of Tebilat Kelim, but in a circumstance when one needs a utensil on Shabbat, he should give it to a gentile and then borrow it.
After Shabbat, the Jew must then go back to the non-Jew and ask if he would return ownership over the utensil. Once he retakes possession over the utensil, he must then immerse it before using it again. If the gentile to whom he gave the utensil will not be coming back – such as if one gave it to a non-Jew whom he did not know, who was just walking in the street or in a store – then since the non-Jew does not come back to retrieve it, he expresses his disinterest in the utensil and the Jew takes ownership over it by default. In such a case, he should immerse the utensil after Shabbat without reciting a Beracha. This is the ruling of the Taz (Rabbi David Halevi Segal, Poland, 1586-1667), cited by the Mishna Berura (Rav Yisrael Meir Kagan, 1839-1933).
This is also an advisable solution for a traveler who spends Shabbat in an area without a Jewish community, and needs a pot for cooking. Since he does not have access to a Mikveh, and cannot use the pot without immersing it, he should find a gentile to whom he can formally give the pot, and then borrow it and use it.
Summary: If a person needs to use a new utensil on Shabbat, he should formally give it to a non-Jew and then ask to borrow it. He may then use it even though it has not been immersed. After Shabbat, he should ask for the utensil back, and then immerse it in a Mikveh.
