Reference for Kelim 8:7

הַשֶּׁרֶץ שֶׁנִּמְצָא בָעַיִן שֶׁל תַּנּוּר, בָּעַיִן שֶׁל כִּירָה, בָּעַיִן שֶׁל כֻּפָּח, מִן הַשָּׂפָה הַפְּנִימִית וְלַחוּץ, טָהוֹר. וְאִם הָיָה בָאֲוִיר, אֲפִלּוּ כַזַּיִת מִן הַמֵּת, טָהוֹר. וְאִם יֶשׁ שָׁם פּוֹתֵחַ טֶפַח, הַכֹּל טָמֵא:

If a <em>sheretz</em> was found in the eye-hole of an oven or of a double stove or of a single stove: If it was outside the inner edge, [the oven or stove] is pure. If it [the oven] was in the open air, even if it was an olive's bulk of corpse, it is pure. If there was [in the eye-hole] an opening of one handbreadth, it is all impure.

Jastrow