Shekalim 4 - From whom they collected half a shekel?
Fifteen days after the proclamation, Temple-appointed moneychangers would set their tables in Jerusalem and elsewhere, to remind the people about their obligation. On the twenty-fifth day they would sit in the Temple, since the time was very close to when the new money will be taken out to buy sacrifices. Later they would even take pledges until people pay. An appointed court official would enter the debtor's house, take a valuable object, and not return it until the half-shekels was paid.
From whom to they take a pledge? From Levite, Israelites, and converts. Women and minors may donate if they want. They did not take pledges from the Kohanim, for the sake of peace. Why? When a Kohen brings a flour offering, it can not be eaten but is rather completely burned . Therefore - reasoned the Kohanim - how can we donate money for sacrifices? If we do, some of the sacrifices that we normally eat would be prohibited to eat! Some even said that any Kohen who gives half-shekel sins. The Sages, however, claim that any Kohen who does not give half-shekel sins, since if he gives wholeheartedly, it becomes the property of the community, and not his own.
Together with the half-shekel, one had to give a small coin ("kolbon"), to compensate for the higher price of the half-shekel at the time of this collection. The Talmud discusses when this kolbon is required and when not, such as cases of donating for another, or two brothers paying from their common estate.
Art: A man counting money by (after) Joos Van Craesbeeck