|Halacha of the day|
/ One must use the light of a candle to do the search. One cannot fulfill the mitzvah with the light of the moon, even if the amount of light is sufficient for the search.
If one did not search during the night, and needs to search during the day (Erev Pesach), one must still use a candle, and also say the Brocho. Some Poskim recommend closing the shades in order to darken the room somewhat.
The candle used for the search should be of a single wick and prefereable of beeswax.One should not use oil lights for the search, unless no candles are available.
The Nitei Gavriel (Pesach 17:19) quotes a number of Poskim that permit the use of a small flashlight in places where searching with a candle is inadvisable and difficult due to the possibility of starting a fire.
[In response to inquiries where Vol. 4 of my Chagaynu on Pesach is available. Tzivos Hashem Bookstore has them and Judaica World will have them at the beginning of the week.]