Shabbos Daf 29 שבת דַף 29

Rava says the reason why R’ Eliezer prohibits use of the cloth wick that was not singed is that a wick that was not charred does not light properly.

Rav Hamnuna said the machlokes between R’ Eliezer and R’ Akiva in the Mishnah whether a cloth wick is mekabel tumah is specifically for a cloth that is less than three by three tefachim, which lost its status of a begged because it was designated for some insignificant use, such as a rag, and then the owner puts it aside by hanging it on a peg or a door.

R’ Eliezer holds that since the owner sets it aside for a later use (by hanging it on a peg or a door), it indicates that he now regards the cloth as significant and the cloth regains its status as a begged. Therefore it is mekabel tumah.

R’ Akiva holds that since the owner only hung the rag on a peg or placed it on a door, it indicates that he did not intend to reestablish their status as a begged, and therefore it is not mekabel tumah.

The Mishnah presents a machlokes between the Rabonim and R’  Yehuda whether one might come to remove oil on Shabbos from the following three  lamps and thereby be liable for mechabeh (extinguishing):