פירוש על כלים 8:3

סרידא (stuffed matting used for stoppers of stones, bag) – a kind of small kneading trough that the baker uses to knead in it and it lacks a receptacle. But Maimonides states that it is a board of perforated earthenware thar is made like a kind of net-work/mat, a netting, which we translate in Aramaic as עובד סרדתא/a person who works in netting.

Netting placed over the mouth of an oven and slightly sinking into it, and having no frame: If a sheretz was in it, the oven becomes unclean; If the sheretz was in the oven, the food in the netting becomes unclean, since only vessels afford protection against an impurity in an earthen vessel. This netting is not considered to be a vessel because it does not have an "inside." Therefore it does not serve as a barrier for impurity vis a vis the oven. This means that if a sheretz was in it, it defiles the oven. And if a sheretz is in the oven, then the food in the netting becomes unclean.

גפיים – rims and handles.

A jar full of pure liquids placed beneath the bottom of an oven, and a sheretz in the oven – the jar and the liquids remain clean. If it was inverted, with its mouth projecting into the air-space of the oven, and a sheretz was in the oven, the liquid that clings to the sides of the jar remains clean. Since the jar is below the oven, the impurity of the oven doesn't spread into the jar. This is true even if the jar is open and there is a hole in the bottom of the oven. As long as the jar is not in the oven's airspace, it is not susceptible. If they put the jar on top of the oven and its mouth is open the liquid which remains in the jar is still pure. Again, this liquid is not in the airspace of the oven, rather above it. Therefore it remains pure.

שאין מצילים מיד כלי חרס (do not save from the power of earthenware vessels/utensils – lacking an inner part) – from being susceptible to defilement from the airspace of an earthenware vessel.

אלא כלים – and this, for since it does not have handles, it is not considered a vessel.

נחושתו של תנור (from the copper rim of the stove) – its bottom and lowest point. And similar to it is found in Ezekiel (16:36): “Because of your brazen effrontery/יען השפך נחשתך, [offering your nakedness to your lovers for harlotry – just like the blood of your children, which you gave to all your abominable fetishes].”

החבית והמשקין טהורים – that they did not enter into its (i.e., the unclean reptile’s) airspace, for they stand below the copper rim of the stove, and even if the jar is open and enters from the airspace of the oven at its mouth, the wine is not defiled through this, for the airspace of an earthenware vessel does not defile neither above nor below other than within.

היתה כפויה – the jug [was turned upside down] on its lip and placed on the lip of the oven which has an unclean reptile in it, and on the rim of the jar the moisture of wine that is in it, moist enough in order to moisten other objects, this moisture is not defiled on account of the airspace of the oven that enters into the jar, because the moisture of the wine was not within the oven.