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How to do Biur Chametz
- The minhag is to burn Chametz (until it becomes coals or ashes) during the day, however, one fulfills the mitzvah by destroying the Chametz in any fashion. 
- It is preferable for one to burn his own chometz and not to appoint someone else to do it for him 
- One should cut the chametz into thin slices in order for it to burn properly. 
- One should leave over at least a Kezayit of chametz that he is not selling to a non-jew in order to properly fulfill this mitzva. 
- It is permitted to throw the chametz into a field with a lot of birds, but if the person notices that at the prohibited time for chametz, the birds haven't eaten it yet, he should destroy it immediately. 
- One fulfills the mitzvah of destroying the Chametz by flushing it down the toilet. 
- It is forbidden to do melacha once the time for burning comes until you burn the chametz. 
- One should burn the chametz until it turns to charcoal 
- If one puts Chametz in one’s private garbage bin one should either pour Ajax on the Chametz to make it totally inedible , or put it in the street and declare that it be ownerless in front of three people. . One can also include them in the sale of the chametz to a non-jew but then they cannot be used by him over pesach. 
- It’s preferable to burn the Chametz without dousing it in gasoline or lighter fluid so that one can destroy the Chametz with fire and not to make it inedible using any other means.  If the chametz will not burn in time without the gasoline then one should pour it to speed up the burning. 
- There is a custom to burn the ten pieces of chametz that were hidden for the bedikah along with the rest of the chametz during biur.  There is also a custom to burn the lulav,  the aravot used for hoshanot , leftover chanuka candles and wicks  and fingernails  along with the chametz.
- One should throw the chametz with his right hand. 
- One should burn the chametz in one's own property. 
- One doesn’t have to do Bitul Chametz after Bedika of the Shul or Bet Midrash  unless it belongs to an individual in which case one should do Bitul Chametz. 
- One should brush his teeth before the prohibited time for chametz arrives. 
- Women are also obligated in the mitzva to destroy chametz. 
Which candle to use
- One should not use a candle torch such as a havdala candle for checking for chametz because it is not possible to insert it into narrow places. 
- Someone who used a torch must repeat the search without a blessing using a single candle. 
- If one does not possess a candle one may use a small flashlight. 
- There is no beracha recited before the burning. The beracha of al biur chametz is recited before the bedika. 
- If someone forgot the beracha the night before on the bedika, he can recite the next day on the burning. 
- One does not recite a blessing when using a flashlight for Biur Chametz. 
- If one did not pray arvit and the time to search for chametz has arrived, one must pray arvit first and then search for chametz. 
- If one is selling his Chametz via his local rabbi, it is preferable to burn his remaining Chametz after the sale takes effect. 
- The burning and the bitul of the chametz should be finished by the end of the fifth hour. Some say that one should specifically burn it at the beginning of the fifth hour. 
- If chametz is found during pesach, see Bedikat_Chametz#If_one_finds_Chametz.
- The nullification during the day should be done before the sixth hour, so that the chametz that you nullify is still yours when you nullify it.  but after the burning. 
- If one leaves his house, he should still do bitul when the time comes. 
Erev Pesach on Shabbat
- When the fourteenth of Nisan occurs on a Shabbat, all chametz must be destroyed before shabbat except for the chametz that will be needed for the first two shabbat meals. 
- Rama 445:1, Mishna Brurah 445:1-2, Chazon Ovadia part 1 page 64. Kaf Hachayim 445:3-4. This is based on the Mishna in Pesachim 21a which records an argument regarding how to fulfill the obligation in Shemot 12:15 תַּשְׁבִּיתוּ שְּׂאֹר מִבָּתֵּיכֶם. Rabbi Yehuda says the only way is to burn while chachamim say you can burn it, crumble it, or throw it into the river. Even though the Shulchan Arukh (445:1) rules that one may dispose of chametz in any fashion, Rama 445:1 writes that the minhag is to specifically burn it in order to satisfy all opinions. The Gra 445:1 says that even chachamim say that ideally one should burn it, as the Mishnah states one can "even" (af) eliminate it in other ways. He adds that the only reason this is only a custom and not obligatory is because according to rabbi yehuda you need to burn the chametz after its prohibited time and since we do it before that we can really do it any way. Kaf Hachayim 445:11 says that there is special kabbalistic importance to burning the chametz because it symbolizes burning the evil inclination.
- Kinyan Torah 5:37
- Chazon Ovadia Pesach page 40.
- Mishna Brurah 445:10, Kaf Hachayim 445:18.
- Chazon Ovadia page 65.
- Piskei Teshuvot 445:4, Mishna Brurah 445:5. Kinyan Torah 2:86 quotes the Chazon Ish 118:3 that he reluctantly agrees that the modern toilet is similar to throwing it into the ocean.
- Chazon Ovadia Part 1 page 65 based on Magen Avraham 445:2.
- Mishna Brurah 445:1, Shulchan Aruch Harav 445:4, Kaf Hachayim 445:3.
- Minchat Yitzchak 4:56, Shevet Halevi 1:137.
- Piskei Teshuvot 445:7, Chelkat Yaakov 3:165
- Be'er Moshe 1:41; 3:74
- Halichot Shlomo 6:10, Piskei Teshuvot 445:1, Beer Moshe 5:122, Siddur Pesach Kihilchato page 173.
- Kaf Hachayim 432:1 quoting the Arizal, Chazon Ovadia 5763 Pesach Part 1 page 36.
- Rabbi Mansour on dailyhalacha.com. Hagahot Maimoniot Hilkhot Sukkah 7:26 and Darchei Moshe Haaroch 664 and the Rama 664:9. Kaf Hachayim 445:16, 664:60 says to take half of the lulav to burn with the chametz and half to bake the matzot. The custom in Yemen was to use it to feul the ovens for matza according to Rav Yosef Kapach in Halikhot Teiman page.
- Mishna Brurah 445:7
- Rabbi Mansour on dailyhalacha.com. See also Leftover oil and wicks of Chanukah candles.
- Chazon Ish quoted in Orchot Rabbeinu page 104
- Orchot Chaim 451:1.
- Teshuvot vihanhagot 1:192 quoting the Ramban that the mitzva from the torah to burn chametz only applies to chametz in your domain.
- Mishna Brurah 433:43, Aruch HaShulchan 433:12
- Halachos of Pesach (Rabbi Eider; pg 73)
- Chazon Ovadia part 1 page 63, Ben Ish Chai Parashat Tzav halacha 8, Kaf Hachayim 444:32, Yechave Daat 1:91:8.
- Sefer Hachinuch Mitzva 9, Chazon Ovadia pesach 5763 part 1 page 57. Pri Megadim Introduction to Hilchot Pesach 7 says that women are exempt from destroying chametz.
- Chazon Ovadia page 38
- Chazon Ovadia page 38
- Chazon Ovadia page 38
- Shulchan Aruch 432:1. Mishna Brurah 432:3 explains that this is because bedika is considered the beginning of the biur, and the bitul is done mainly in the heart and you can't say a beracha on something done in your heart.
- Mishna Brurah 423:4
- Or Letzion 7.8
- Chazon Ovadia page 44
- * The Mishna (Pesachim 21a) records a dispute between Rabbi Yehuda, who holds that one must burn one’s Chametz in order to fulfill Biur Chametz, and Rabanan, who say that one can fulfill Biur Chametz even by throwing it to the wind or into the ocean. The Rosh (2:3) quotes a dispute amongst the Rishonim regarding which opinion is normative. While the S”A 445:1 rules like Rabanan, the Rama says the Minhag is to burn it.
- Rabbi Mordechai Willig (Am Mordechai Moadim p. 152-3) defends the Minhag of those who burn the Chametz in the morning before going to work even though it is before the Rabbi sells the rest of their Chametz. He explains that even though they aren’t burning their last K’zayit, nonetheless, they fulfill Tashbitu when the Rabbi sells the Chametz on their behalf. He bases this argument on the Tur 436, who according to the Pri Chadash 436:3, holds that selling one’s Chametz to a non-Jew is a fulfillment of Tashbitu. He adds that even though there is a Mitzvah to burn the Chametz, Rosh and Beit Yosef maintain that if one gets rid of his Chametz before the fifth hour, even Rabbi Yehuda agrees that one need not burn it.
- Rabbi Hershel Schachter (B’ikvei HaTzon p. 76) argues that some Rishonim hold that one does not fulfill Tashbitu by selling one’s Chametz (see Tosfot Rabbenu Peretz Pesachim 28b). Accordingly, if one burns his Chametz in the morning before the Rabbi sells the rest of one’s Chametz, one might not fulfill Tashbitu. Furthermore, the Bracha one made before Bedikat Chametz may turn out to be a Bracha Levatala. Rabbi Schachter also stated his opinion on the OU Pre-Pesach Webcast 5771 between minutes 28:30 and 30:15 and in a shiur on yutorah.org (“Halachos of Pesach,” min 3-6). See an article in Kovetz Aharon VeYisrael about whether one fulfills Tashbitu with selling his chametz to a non-Jew.
- Shulchan Aruch 434:2, Mishna Brurah 434:12, Kaf Hachayim 434:38-40. Theoretically, one may burn one’s chametz until halakhic midday (Mishnah Pesachim 11b); however, Mishna Brurah (434:12) writes that in order to perform bitul chametz after biur chametz, one must burn it before the end of the fifth hour.
- Piskei Teshuvot 445:3. The gemara in pesachim 21a says that from the torah chametz is only forbidden at mid-day, the rabbis made it two hours earlier because people might get confused with the hours. Rambam Chametz U'matza 1:9.
- Shulchan Aruch 434:2
- Rama 434:2. According to Rav Yaakov Emden in Mor Uketzia 434 one can do the bitul before the burning even lechatchila.
- Shulchan Aruch 236:1.
- Shulchan Aruch 444:1, Rambam Hilchot Chametz U'matza 3:3 based on Rabbi Meir's opinion on Pesachim 49a.