When you buy metal or glass utensils that are used for food from a non-Jew, even when they are new, you may not use them for any [food related] purpose even if the food is cold, unless they are immersed in a natural spring or mikvah, that is valid for the ritual immersion of women at the end of the menstrual period. The purpose of this immersion is to elevate these utensils from the impurity of heathen ownership to the holiness of Jewish ownership. Before the ritual immersion, the following berachah is recited, if you are immersing one utensil, say, Baruch ata Adonoy, Elokeinu melech haolam asher kideshanu bemitzvosav vetzivanu al tevilas keili. for two or more say, asher kideshanu bemitzvosav vitzivanu al tevilas keilim.

Since the utensils must be immersed only in a place that is valid for the immersion of women, therefore, care must be taken not to immerse them in rivers when they are fuller than usual from abundant rains, and melting snow. This occurs very frequently before Pesach when the rivers rise, and [still] people use them to immerse utensils; and this is not proper¹ (21), in extreme circumstances, one may rely on those authorities that are lenient in this situation. (see Chapter 162:12, 13).

footnotes: ¹ According to Shulchan Aruch

Wooden utensils do not require immersion, but if they have metal hoops, they should be immersed without reciting the berachah. Similarly, earthenware need not be immersed. But if they are plated on the inside with lead, i.e. glazed, they must be immersed [but] without reciting the berachah. The same law applies to 'porcelain' vessels.²

footnotes: ² Some authorities, however, do not require immersion for porcelain. Immersion is also not required for utensils made from plastics.

If an old utensil was used by a non-Jew in such a manner that it required [halachic] kashering such as placing it in boiling water, or making it red hot through direct flame, it must first be kashered and then immersed.

If you borrow or rent a utensil from a non-Jew, you do not have to immerse it. But if you borrow or rent utensils from a Jewish merchant, you have to immerse them, but without reciting the berachah. The merchant should then inform subsequent buyers [of the immersion], so that they do not immerse them [again] and recite an unnecessary berachah.

If a factory that manufactures glass utensils is owned by a Jew but whose workers are non-Jews, the utensils that are manufactured there must be immersed without saying the berachah.³ 73: 4)

footnotes: ³ Some later authorities disagree with this ruling and maintain that immersion is not required when the factory is owned by a Jew. (See Chochmas Adam

If a Jew gave silver or other metals to a non-Jewish craftsman to have him make a utensil, or repair a utensil that had a hole, and could not hold a revi'is,⁴ [the vessel] must be immersed without reciting the berachah.

footnotes: ⁴ See glossary.

Immersion is required only for a utensil used for food which is ready to be eaten immediately without any other preparation. The iron tools used to prepare the matzos, or to cut the dough, and the needle used to sew the [gullets for] stuffing, or similar things do not require immersion. Since a knife used for slaughtering or for skinning an animal, can be used for prepared food, and also trays upon which matzos are placed, require immersion but without reciting the berachah. A tripod upon which pots are placed need not be immersed since the food itself does not touch the tripod. But a metal spit upon which meat is roasted, should be immersed and a berachah recited. Some authorities hold, that large glass utensils [pitchers] that are not used for drinking, but rather to hold liquid to be poured into drinking cups, are not considered meal-related and do not require immersion. Other authorities, however, say that they should be immersed. They should, therefore, be immersed without reciting the berachah.

A pepper grinder, must be immersed because of its metal part, but since the bottom part into which the pepper falls, is made of wood, it need not be immersed. A coffee grinder should be immersed without reciting the berachah.

Care must be taken that a utensil be completely clean, and free of any dirt or rust before immersing. (However, a rust stain or other dark spots that commonly appear on utensils, and of which people are not particular do not invalidate the immersion process.) The entire utensil must be submerged at one time, so that the whole utensil is in the water [at the same time]. A utensil and its handle, must be submerged in the water at one time. If the person immersing the utensil intends holding it in his hand [during the immersion], he should first immerse his hand in the place where he will immerse [the vessel]. The utensil should not be held tightly, but rather with an ordinary grip. If the immersion is done by tying the utensil to a rope, as, for example, it is being immersed in a well, care must be taken that the knot is loose so that the water may reach every part of the utensil.

When immersing vessels with a narrow mouth, be very careful that they remain immersed until they fill up with water, because it is necessary for the water to cover the utensil from inside and outside.

Minors, either male or female, should not be entrusted with the immersion of utensils.

It is forbidden to immerse utensils on Shabbos or Yom Tov. If you forgot to immerse them prior [to Shabbos or Yom Tov, and do not have any substitute] give them to a non-Jew as a gift and then borrow it from him. If it is the type of utensil that can be used to draw water, in an area where it is permissible to carry, draw water with it [from a mikvah] and bring it home. This will not appear as a ritual immersion, but the berachah should not be recited.