Shekalim 3:4-4:1

Shekalim 3:4

The first withdrawal was made (15 days before Passover) and he covered the shekels remaining in the chest with leather covers (so that subsequent donations would be separated on top). After the second withdrawal (15 days before Shavuos) he did likewise. After the third withdrawal (15 days before Succos) he did not cover the remaining coins because the purpose of the covers is to keep one from withdrawing from the same pool a second time and after this there was no subsequent withdrawal in which one might err. The first withdrawal was from shekels donated by those living in Israel, the second was from places close to Israel and the third was from Babylonia, Medea and distant lands.

Shekalim 4:1

The money withdrawn was used to purchase animals for the twice-daily tamid offerings, the musaf offerings and their libations, the omer offering, the two loaves and the showbread, and all communal offerings. Those who watched what grew in the Sabbatical year were paid from these funds. Rabbi Yosi said that a person could volunteer to perform this service for free; the Sages said that he must agree that offerings had to be purchased using communal funds.