1,226. The Value of the Kolbon
Shekalim 3:6
If a person gives a whole shekel to the Temple treasury to pay his own half-shekel and to receive a half-shekel that was collected from someone else as change, he must pay the fee (kolbon) twice (because he is performing two transactions). If he donates the whole shekel in its entirety, he must only pay one kolbon.
Shekalim 3:7
When a sela was the standard denomination so that two dinar were given as the half-shekel, the kolbon was half a maah, which is 1/12 of a dinar. A kolbon was never smaller than this. The kolbon did not have the same status as the shekels that the people donated so the money-changers would collect and store them separately until such time as the funds were needed by the Temple treasurers.