The Magen Avrohom (Orech Chaim 670) writes that there is a custom for the children of poor people to go collecting from door to door on Chanukah.
Sefer Sifsei Tzadik writes that when the Magen Avrohom refers to children, this can be understood as a reference to those who are “young” in the sense that they do not possess many mitzvos, due to having left the proper path. They are poor in the sense that they lack proper wisdom to do what is right.
On Chanukah, they are able to come to the door. With the mezuzah on one side of the door and the menorah on the other, the door is open to bring back those who have strayed.
This idea is seen from the explanation of the Chidushei Harim zy”a on the Gemara’s words (Shabbos 21A) that the types of wicks and oil that may not be used for Shabbos may be used for Chanukah. He understands this to mean that even if there are people who cannot be brought back through the holiness of Shabbos due to the fact they have strayed so far, they can be brought back through the light of Chanukah. Therefore, Chanukah is a truly auspicious time for kiruv rechokim.
