Beitza 2:2-3

Beitzah 2:2

If yom tov falls after Shabbos, Beis Shammai say that one immerses both himself and his utensils before Shabbos; Beis Hillel say that utensils are immersed before Shabbos and people immerse on Shabbos.

Beitzah 2:3

Beis Hillel and Beis Shammai agree that one may put ritually-impure drinking water into a stone vessel and immerse it on yom tov but one may not do this with a vessel of other materials. (A stone vessel cannot contract ritual impurity; other vessels can and they may therefore not be immersed on yom tov.) One may immerse an already-ritually-pure utensil in order to prepare it for a higher degree of sanctity (e.g., for use with terumah) and to transfer from one group to another vis-à-vis the Passover offering.