Mishnah Taharos 8:9: A stick which is full of impure liquid, once it touches a mikvah it becomes pure, according to Rabbi Yehoshua. And the Sages say: [it is not rendered pure] until one immerses its entirety. A shower [of liquids being poured], or [liquids flowing down] an incline, or a dripping liquid [enough to make something else wet, but not enough to, in turn, wet something else], these do not constitute a connection for impurity or for purity [i.e. if part of them is rendered pure or impure it does not affect the purity status of the rest]. But a pit [of stagnant water] does constitute a connection for impurity and for purity.

מַקֵּל שֶׁהִיא מְלֵאָה מַשְׁקִין טְמֵאִין, כֵּיוָן שֶׁהִשִּׁיקָהּ לַמִּקְוֶה, טְהוֹרָה, דִּבְרֵי רַבִּי יְהוֹשֻׁעַ. וַחֲכָמִים אוֹמְרִים, עַד שֶׁיַּטְבִּיל אֶת כֻּלָּהּ. הַנִּצּוֹק וְהַקְּטַפְרֵס וּמַשְׁקֶה טוֹפֵחַ, אֵינָן חִבּוּר לֹא לַטֻּמְאָה וְלֹא לַטָּהֳרָה. וְהָאֶשְׁבֹּרֶן, חִבּוּר לַטֻּמְאָה וְלַטָּהֳרָה:

Mishnah Taharos 9:1: Starting when are olives able to be rendered impure [by being primed for impurity by a liquid]? Once they sweat moisture in the vat [into which the olives are placed for them to soften for pressing], but not by moisture in the basket [into which they are placed after being picked], according to Beit Shammai. Rabbi Shimon says: the measure for sweat is three days [i.e. the moisture the olives sweat while in the vat does not prime them for impurity until they have been there for three days]. Beit Hillel says: when [they soften such that] three connect to one another [only then does the moisture that emerges from them prime them for impurity]. Rabban Gamliel says: once their work has been finished [i.e. once no more olives are being added to the vat, and they are ready to be brought to the olive press]; and the Sages say in accordance with him.

זֵיתִים מֵאֵימָתַי מְקַבְּלִין טֻמְאָה. מִשֶּׁיַּזִּיעוּ זֵעַת הַמַּעֲטָן, אֲבָל לֹא זֵעַת הַקֻּפָּה, כְּדִבְרֵי בֵית שַׁמָּאי. רַבִּי שִׁמְעוֹן אוֹמֵר, שִׁעוּר זֵעָה שְׁלשָׁה יָמִים. בֵּית הִלֵּל אוֹמְרִים, מִשֶּׁיִּתְחַבְּרוּ שְׁלשָׁה זֶה לָזֶה. רַבָּן גַּמְלִיאֵל אוֹמֵר, מִשֶּׁתִּגָּמֵר מְלַאכְתָּן. וַחֲכָמִים אוֹמְרִים כִּדְבָרָיו: