Kelim, Chapter Twenty-Eight, Mishnah Three
1) If a bandage is made of cloth or leather it is pure.
a) (Rabbi Yose says: with leather it is pure.)
2) A poultice is pure if it is on cloth, but if on leather it is susceptible.
a) Rabban Shimon ben Gamaliel says: even if it was on cloth it remains susceptible to uncleanness because it can be shaken off.
Section one: A piece of cloth or leather that is used as a bandage on a wound will not afterwards be used for another purpose. Therefore, it is pure. Serving as a bandage is not sufficient for it to be considered susceptible to impurity.
Rabbi Yose’s words are not found in many manuscripts of the Mishnah and they are probably out of place here. There actual context is mishnah six.
Section two: If one puts a poultice on cloth, the cloth will no longer be used for another purpose. Therefore it is pure. However, if he puts it on leather, the leather can be cleaned off and reused. Therefore, the leather remains susceptible to impurity. Rabban Shimon ben Gamaliel holds that even if put on cloth the poultice could be shaken off and the cloth reused. Therefore, the cloth also remains susceptible to impurity.