Guernsey Police are now appealing for witnesses following the break-in at the Admiral Park shop, that took place sometime between 18:00 on Friday 10 August and 09:00 the following Monday.
The burglars broke through the door on the Bouet side of the shop.
In the process, they caused minor damage to the door, which was found to be insecure when staff returned to the shop, and also to the table where the metal cash deposit box was fixed to, and subsequently broken away from.
Police said they believed that they cash deposit box was empty though, as it was not often used by the shop staff. The charity box was expected to have a small amount of loose change inside though.
Anyone who was in the area at the time and saw anything suspicious or thinks they may be able to identify those responsible is asked to contact PC 135 Simmonds at Police Headquarters on 725111, or call Crimestoppers, anonymously on 0800 555 111.