Kelim, Chapter Twenty-Five, Mishnah Six
1) The bases, rims, hangers or handles of vessels that have a receptacle upon which an unclean liquid fell, one dries them and they remain clean.
2) But [if unclean liquid fell] on any part of any other vessel which cannot hold pomegranates (or in which no distinction is made between its outer and inner sides), the whole becomes unclean.
3) If the outer side of a vessel contracted uncleanness from a liquid, only its outer side is unclean but its inner side, rim, hanger and handles remain clean.
a) If its inner side contracted uncleanness the whole is unclean.
Section one: If an unclean liquid falls on an ancillary part of a vessel, such as its base, rim, hanger or handle, the entire vessel need not be immersed in the mikveh. It is sufficient to dry off the liquid and the vessel will remain clean. However, this is true only if the vessel is one that has a receptacle. In such a case we can distinguish between the main part of the vessel and its ancillary parts.
Section two: If the vessel cannot hold pomegranates, meaning it does not have a proper receptacle (see 17:1, 4), then no matter where the unclean liquid falls the whole vessel is impure. Alternatively, if the vessel is the type that is not considered to have an inside or an inside, which would preclude vessels with receptacles, then similarly the impure liquid defiles the whole thing. In such cases we can’t distinguish between the main part of the vessel (the receptacle) and the ancillary parts, so we must treat the entire vessel as impure.
Section three: This section contains the general rule that has been mentioned throughout the chapter. If the outside becomes unclean, the inside is still clean, but if the inside becomes unclean, the outside is unclean.
It is interesting to note that the Mishnah waits a full six mishnayot before providing us with the background which we need in order to understand what we’re talking about. This demonstrates that the Mishnah is not a didactic text meant to teach students who do not know the Mishnah’s laws. Rather, the Mishnah is better understood as a recording of the main halakhot and some discussions that serve as the background to rabbinic law and culture. Put another wayin order to understand the Mishnah, you have to already know the Mishnah. If this makes it a bit frustrating for the beginning student, you can be thankful that we have two thousand years of commentary to help us along the way!