One of the biggest problems with the micro:bit is broken wires on the Batttery Cases. The on/off switch on our battery cases helps but we still use to break lots of them until we found this cool tool.  It is desigend to remove the battery case, without breaking the wire, from the micro:bit or the edge connector.
One side is sized to remove the AAA battery pack from the micro:bit. The other side is sized to remove the larger connector for the AA battery pack connected to the edge connector.