Mishnayos Keilim Perek 28 Mishnah 5

כיפה – a wrap that is on the head of a woman. And it has defilement through treading, for sometimes she sits upon it.

ונתנו על הספר – if he designated it for a Scroll and wrapped it upon it (i.e., the Scroll).

טהור מן המדרס – but it is impure regarding other defilements.

חמת (waterskin) – a bottle made of [leather] hide.

שעשאו שטיח – a hide stretched on the ground to sit upon it. And a waterskin and a rug are both impure through treading/Midras, and even so, since they are different one from the other, and even without the change of action, it is like a vessel that is broken and is pure, but it is susceptible to receive defilement from here onwards.

כסת שעשאו מטפחת ומטפחת שעשאו כסת טהור (a bolster/cushion that one made into a wrap and a wrap that one made into a bolster/cushion is pure) – And we don’t have the reading of טמא/impure [as does the Mishnah]. And this is the reading of my Rabbis/teachers. And similarly, I found in an accurate Mishnah. And this is proved from the Tosefta (see Tosefta Kelim Bava Batra, Chapter 6, Halakha 1), and the reason that in all of them, it is pure, as is taught in the Mishnah close by (our Mishnah): “This is the general principle: Anything which one changed for [something] in its own category is impure, and for [something in] another category is pure./"זה הכלל: כל ששנהו לשמו – טמא, לשם אחר – טהור"’, and it explains in the Tosefta: for something in its own category – from a flat vessel to a flat vessel, as for example, from a rug to a wrap or from a wrap to a rug, and in another category, from a simple vessel to a receptacle or from a receptacle to a simply vessel, and also from one receptacle to another receptacle, everything that is a change that is not in its own category is ritually pure. And if so, the waterskin that was made into a bag that he changed it from one [kind of] receptacle to another kind of receptacle is also ritually pure. But if you raise the question, why didn’t they combine them and teach them [together] a waterskin that was made into a rug and a rug that was made into a waterskin at the same time, since all of them are ritually pure. But it is not difficult, because he needed to go back and teach [waterskin] another time, as it taught the waterskin that was made into a bag, and he would have had to teach a waterskin that was made into a rug or a bag, and he didn’t want to change fro the order of the other things. But most of the books have the reading of "טמא"/impure, and I don’t know how to resolve this “reading” correspondingly.