אַחַת עֶשְׂרֵה מַעֲלוֹת עָשׂוּ חֲכָמִים לַקֹּדֶשׁ עַל הַתְּרוּמָה וְאֵלּוּ הֵן. יֵשׁ לְאָדָם לְהַטְבִּיל כֵּלִים בְּתוֹךְ כֵּלִים לִתְרוּמָה אֲבָל לֹא לְקֹדֶשׁ. גְּזֵרָה שֶׁמָּא יִהְיֶה פִּי הַכְּלִי צַר וְלֹא יִהְיֶה בּוֹ כִּשְׁפוֹפֶרֶת הַנּוֹד וְנִמְצְאוּ הַכֵּלִים שֶׁבְּתוֹכוֹ כְּאִלּוּ טָבְלוּ בְּמַיִם שֶׁבַּכְּלִי לֹא בַּמִּקְוֶה. בַּמֶּה דְּבָרִים אֲמוּרִים כְּשֶׁהָיָה הַכְּלִי הַגָּדוֹל שֶׁיֵּשׁ בְּתוֹכוֹ הַכֵּלִים הַטְּמֵאִין טָהוֹר. אֲבָל אִם הָיָה טָמֵא מִתּוֹךְ שֶׁעָלְתָה לוֹ טְבִילָה עָלְתָה טְבִילָה לַכֵּלִים שֶׁבְּתוֹכוֹ אֲפִלּוּ לְהִשְׁתַּמֵּשׁ בָּהֶן בַּקֹּדֶשׁ:
Our Sages established eleven stringencies applying to consecrated foods that do not apply to terumah. They are the following: A person may immerse keilim inside other keilim to use for terumah, but not those to be used for consecrated foods. This is a decree lest the opening of the container be narrow and not be as wide as the mouthpiece of a drinking pouch. Thus the keilim inside of it would be considered as if they were immersed in the waters of the k'li and not in the waters of the mikveh. When does the above apply? When the large container in which the small impure keilim were placed was pure. If, however, it was impure, since the immersion is valid for it, it is also valid for the keilim inside of it, even though they were to be used for consecrated foods.
