Siman 448
Presented here for study, not as a practical ruling. The Shulchan Aruch rules by Sephardi custom, the Rema's glosses by Ashkenazi custom, and the Kitzur follows Ashkenazi custom. For a practical question, ask your rabbi.
א חָמֵץ שֶׁל עַכּוּ"ם שֶׁעָבַר עָלָיו הַפֶּסַח, מֻתָּר אֲפִלּוּ בַּאֲכִילָה.
1 The Law of Chametz Over Which Passover Has Passed. And It Contains Seven Sections: Chametz belonging to a non-Jew over which Passover has passed is permitted even for consumption.
ב אִם עַכּוּ"ם מֵבִיא לְיִשְׂרָאֵל דּוֹרוֹן חָמֵץ בְּיוֹם אַחֲרוֹן שֶׁל פֶּסַח, לֹא יְקַבְּלֶנּוּ הַיִּשְׂרָאֵל, וְגַם לֹא יְהֵא נִכָּר מִתּוֹךְ מַעֲשָׂיו שֶׁחָפֵץ בּוֹ; וְטוֹב שֶׁיֹּאמַר שֶׁאֵינוֹ רוֹצֶה שֶׁיִּקְנֶה לוֹ רְשׁוּתוֹ.
2 If a non-Jew brings a Jew a gift of chametz on the eighth day of Passover, the Jew should not accept it, and also should not show through his actions that he desires it. And it is good that he should say that he does not want [the chametz] to be acquired for him in his domain.
ג חָמֵץ שֶׁל יִשְׂרָאֵל שֶׁעָבַר עָלָיו הַפֶּסַח, אָסוּר בַּהֲנָאָה אֲפִלּוּ הִנִּיחוֹ שׁוֹגֵג אוֹ אָנוּס. וְאִם מְכָרוֹ אוֹ נְתָנוֹ לְעַכּוּ"ם שֶׁמִּחוּץ לַבַּיִת קֹדֶם הַפֶּסַח, אַף עַל פִּי שֶׁהַיִּשְׂרָאֵל מְכָרוֹ לְעַכּוּ"ם, וְיוֹדֵעַ שֶׁלֹּא יִגַּע בּוֹ כְּלָל אֶלָּא יִשְׁמְרֶנּוּ לוֹ עַד לְאַחַר הַפֶּסַח, וְיַחֲזֹר וְיִתְּנֶנּוּ לוֹ, מֻתָּר, וּבִלְבַד שֶׁיִּתְּנֶנּוּ לוֹ מַתָּנָה גְּמוּרָה בְּלִי שׁוּם תְּנַאי, אוֹ שֶׁיִּמְכְּרֶנּוּ לוֹ מְכִירָה גְּמוּרָה בְּדָבָר מוּעָט; אֲבָל מַתָּנָה עַל מְנַת לְהַחֲזִיר לֹא מְהָנֵי.
3 Chametz belonging to a Jew over which Passover has passed is forbidden in benefit, even if he left it [in his possession] by mistake or under duress. And if he sold it or gave it to a non-Jew who is outside the house before Passover—even though the Jew acknowledges to the non-Jew and knows that he will not touch it at all, but will guard it for him until after Passover and will then return and give it back to him—it is permitted, provided that he gives it to him as an absolute gift without any condition, or that he sells it to him in an absolute sale for a small amount. But a gift on condition to return it does not work.
ד רַשַּׁאי יִשְׂרָאֵל לוֹמַר לְעַכּוּ"ם בְּשָׁעָה חֲמִישִׁית אוֹ קֹדֶם: עַד שֶׁאַתָּה לוֹקֵחַ חָמֵץ בְּמָנֶה קַח בְּמָאתַיִם שֶׁמָּא אֶצְטָרֵךְ וְאֶקָּחֶנּוּ מִמְּךָ אַחַר הַפֶּסַח; אֲבָל לֹא יִמְכֹּר לוֹ וְלֹא יִתֵּן לוֹ עַל תְּנַאי, וְאִם עָשָׂה כֵן הֲרֵי זֶה עוֹבֵר בְּבַל יֵרָאֶה (שְׁמוֹת יג, יז) וּבַל יִמָּצֵא (שְׁמוֹת יב, יט).
4 A Jew is permitted to say to a non-Jew in the fifth hour or earlier: While you are acquiring chametz for one hundred [coins], acquire [it] for two hundred, as perhaps I will need [chametz] and I will buy it from you after Passover. But he may not sell it to him or give it to him on condition [that he will return it], and if he did so, he transgresses [the prohibitions of] 'it shall not be seen' and 'it shall not be found.
ה חָמֵץ שֶׁנִּמְצָא בְּבֵית יִשְׂרָאֵל אַחַר הַפֶּסַח, אָסוּר אַף עַל פִּי שֶׁבִּטֵּל.
5 Chametz that is found in a Jew's house after Passover is forbidden, even though he nullified it.
ו אָסוּר לְהַאֲכִיל חֲמֵצוֹ בְּפֶסַח אֲפִלּוּ לְבֶהֱמַת אֲחֵרִים אוֹ שֶׁל הֶפְקֵר.
6 It is forbidden to feed one's chametz during Passover, even to animals belonging to others or to ownerless animals.
ז אָסוּר לִתֵּן בְּהֶמְתּוֹ לְעַכּוּ"ם לְהַאֲכִילָהּ בִּימֵי הַפֶּסַח, אִם הוּא יוֹדֵעַ שֶׁמַּאֲכִיל אוֹתָהּ פְּסֹלֶת שְׂעוֹרִים שֶׁהוּא חָמֵץ.
7 It is forbidden to give one's animal to a non-Jew to feed during the days of Passover if one knows that he feeds it barley refuse, which is chametz.