If a Jew buys or is given metal or glass kitchenware made by a non-Jew, there is a mitzva to immerse them in a mikveh to purify them. Even if the pots, glasses, or utensils were bought in a Jewish store, they must be immersed if they were produced in a factory owned by non-Jews. Until an item has been immersed, it should not be used. Before immersing an item, the following blessing is recited: “Blessed are You, Lord our God, King of the universe, Who sanctified us with His mitzvot and commanded us about immersing utensils.”
What is the purpose of this immersion? To elevate the kitchenware from being merely an item used for eating (which can involve temptations and challenges to self-control) to being an item enabling Jews to eat in the context of Torah values. This is similar to the immersion a person must undergo when converting to Judaism. Accordingly, converts do not need to immerse their kitchenware, because their own immersion sanctifies their utensils as well.
