Related for Chagigah 43:19

There is a greater stringency with consecrated foods than with Terumah: That they immerse utensils [inside other utensils (see GR"A)], cups inside cups, [and] serving platters inside serving platters with respect to [purifying items used for cooking and serving] Terumah, but not with respect to [purifying items for use with] consecrated foods. With respect to consecrated foods, [everything] is placed inside a basket or inside a gorgotni (=גורגותני, a very large basket normally used for straining wine, see Minchat Yitzchak), and he immerses it [all at once]. Abba Shaul says, that is what we used to do with Terumah, but not with consecrated foods. The outer parts (achuraim) and the inner part and handle [of a vessel are considered separate] with regards to Terumah, but not with regards to consecrated foods (Chag. 3:1). Said Rabbi Yosei, this word (achuraim) is the dual form, [and thus we may deduce] that anything that has outer parts and an inner part must also have a handle [that is considered separate for purposes of purity], and anything that lacks outer parts and an inner part does not have a [separate] handle.