1. There is a dispute about what was done with the Kolbonos.
2. People are allowed to combine their Shekalim and buy a large denomination gold coin.
3. However, they were not allowed to buy a precious stone with their Shekalim.
4. The Gemara discusses what happens if the Shekalim are stolen from the messenger.
5. There is a dispute about a person who separated a Machatzis ha'Shekel and then it became lost.
A BIT MORE
1. Some say that they were added to the Shekalim (to buy the public Korbanos for the year). Others say that they were used to buy Korbanos when none were being offered. A third opinion is that they were used for coating the Kodesh ha'Kodashim.
2. This was commonly done when people lived far away from the Beis ha'Mikdash and found it difficult to ship or send all of their coins to the Beis ha'Mikdash. They would change all of their coins into a very valuable gold coin and send it easily to Yerushalayim.
3. This is because it is possible that the value of the stone will fall, causing Hekdesh a financial loss. In contrast, a gold coin is unlikely to fall in value.
4. There are cases in which the people do not pay again, and there are cases in which they do. In any event, if they pay again and the thief is found, the original Shekalim remain Hekdesh but do not count for next year's Shekalim.
5. Rebbi Yochanan: Until his Machatzis ha'Shekel arrives in the hands of the treasurer of Hekdesh, he is obligated to replace it if it becomes lost. Reish Lakish: He does not need to replace it once he separates it for Hekdesh.