The Laws of Pesach part 2 vol.4, no.12
The Sages required us to search our homes for chametz prior to Pesach to ensure that our homes will be chametz free when Pesach arrives. The optimum time to fulfill this duty is the night before Pesach.
One should not engage in any time consuming activity, for example a haircut or a meal, during the half hour prior to nightfall when the search begins. Even learning Torah during this period is not allowed according to many opinions.
Although the basic obligation to search rests on the owner of the house , the owner can appoint an agent to perform the search.
One must search through any area in which chametz was possibly brought. In a house where children are found, all areas where it was possible for the children to bring chametz must be examined. One must also examine his office and car for chametz. One should clean the areas he must examine before the actual search.
It is customary to use a candle to perform the search. Many people will start the search with a candle and then use a flashlight to examine areas in which a candle is either not practical or dangerous.
One who will be travelling within thirty days of Pesach and will not return home before Pesach must perform the search for chametz before he leaves. He can even perform the search two nights before he leaves if he feels that he will be rushed and hurried beause of his departure. However, he may arrange with a Rabbi to sell his chametz prior to the night before Pesach and thereby will not be required to search. If he leaves before thirty days before Pesach and does not intend to return until after Pesach he does not need to perform the search for chametz. However he must verbally nullify any chametz that might be in his possesion. According to some authorities he must dispose of any known chametz. If he plans to return before Pesach he must perform the search according to many authorities.
After the search one should annul all chametz which may still be in his possession but he did not see according to the text which is found in most siddurim. Since he must understand the words of the annulment he can recite it in English. One should also perform the annulment the next morning after he actually burns his chametz.
One who wants to sell his chametz should consult a competent halachic authority.
