סימן קיד סעיף ב
הֶחָמֵץ שֶׁהוּא מוֹכֵר לְאֵינוֹ יְהוּדִי, צָרִיךְ שֶׁלֹּא יְהֵא בְּבֵיתוֹ שֶׁל יִשְֹרָאֵל. וְאִם הָאֵינוֹ יְהוּדִי לוֹקֵחַ אֶת הֶחָמֵץ לְתוֹךְ בֵּיתוֹ, מַה טּוֹב. וְאִם אִי אֶפְשָׁר שֶׁיִּקָחֵהוּ לְבֵיתוֹ, צָרִיךְ לְהַשְׂכִּיר לוֹ אֶת הַחֶדֶר שֶׁהֶחָמֵץ מֻנָּח בּוֹ. וְצָרִיךְ לִכְתּוֹב בִּשְׁטָר שֵׁם הַקּוֹנֶה, וּבְכַמָּה הִשְׂכִּיר לוֹ אֶת הַחֶדֶר, וְשֶׁאַגַב קַרְקַע הִקְנָה לוֹ אֶת הֶחָמֵץ הַמֻּנָּח שָׁם, וְיִפְרוֹט אֶת כָּל הֶחָמֵץ בְּכַמָּה מָכַר לוֹ, אֲבָל אֵינוֹ צָרִיךְ לִפְרוֹט סְכוּם הַמִּדּוֹת, וְיוּכַל לִכְתֹּב רַק בְּעַד כַּמָּה כָּל מִדָּה עַד לַמְּדִידָה (עַיֵן פְּרִי מְגָדִים). וְכָל מַה שֶּׁכָּתוּב בַּשְּׁטָר, יְדַבֵּר עִם הַקּוֹנֶה גַּם בְּעַל פֶּה. וִיקַבֵּל מִמֶּנּוּ עֵרָבוֹן (דראנגאבע) וּשְׁאָר הַמָּעוֹת יִזְקוֹף עָלָיו בְּמִלְוֶה; וִיהֵא הַכֹּל כָּתוּב בִּשְׁטָר, וְגַם יִמְסוֹר לוֹ אֶת הַמַּפְתֵּחַ מִן הַחֶדֶר. חָמֵץ שֶׁהוּא בְּתוֹךְ כְּלִי הַצָּרִיךְ טְבִילָה (כְּשֶׁלּוֹקְחוֹ מִן הָאֵינוֹ יְהוּדִי), לֹא יִמְכְּרֶנוּ עִם הַכְּלִי, כִּי לְאַחַר הַפֶּסַח כְּשֶׁיַּחְזוֹר וְיִקְנֵהוּ מִן הָאֵינוֹ יְהוּדִי יִצְטָרֵךְ טְבִילָה מֵחָדָשׁ (סִימָן תמ"ח. ופתחי תשובה ביורה דעה סִימָן ק"כ).
The chametz sold to the non-Jew, may not remain in the house of the Jew. If the non-Jew takes the chametz into his own house, so much the better. But if he cannot take it to his home, then you must rent to him the room in which the chametz is (stored). You must mention in the bill of sale the name of the buyer and the amount for which the room was rented, and that by means of the rental of the room, you are transferring to him the ownership of the chametz that is contained in it.2Most later Poskim rule that ownership of chametz in the room can also be transferred to the non-Jew, by means of the rental or sale of the room. This particular form of kinyan (ownership transferred), called kinyan agav, is considered, by many Poskim, the best form of kinyan, and it does not require that the articles, which are sold, actually be in the room. (Ibid. 448:17,19) You should list all the chametz, stating the price of each item,3According to Choshen Mishpat 200:7, it is not necessary to list or state the price of each item. It is sufficient if the buyer agrees to rely on the evaluation of three people or even one person. This is the custom that is prevalent in our form of selling chametz. but you need not mention their weights and measures. You may simply write how much you charge per measure. All that is written in the contract should be discussed orally with the buyer. You should take a deposit from him, and the balance of the purchase price should be considered as a loan. All of the above should be written in the contract. You must also deliver to the buyer the key to the room.4It is also acceptable, if you tell him that you will make the key available to him, whenever he desires to enter to take his chametz. (Ibid. 448:12) If any chametz is in a vessel that requires tevilah (ritual immersion) when bought from a non-Jew, you should not sell it with the vessel, because (if you do sell it), then, after Pesach, when you buy it back from the non-Jew, you will have to immerse it again.
תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא שנאמר הליכות עולם לו אל תקרי הליכות אלא הלכות (נדה ע"ג.)