HERE is a pictureRed Circle:
1. Open the extra battery with a knife or a screwdriver.
2. Remove the top of the battery, and pull back the motherboard
3. Remove the leg indicated by the red circle (Farthest left, as shown), it is better do this by soldering it!
4. Fold the motherboard back down, and replace the top of the battery
Scotch tape works perfectly to hold the battery together.
5. If you want to turn it back into a normal battery, re-solder the leg down.
Blue Square:
1. Open the extra battery with a knife or a screwdriver.
2. Remove the top of the battery, and pull back the motherboard.
3. Scrape away part of the trace (Preferably perpendicular to) indicated by the blue square.
4. Fold the motherboard back down, and replace the top of the battery
Scotch tape works perfectly to hold the battery together.
5. If you want to turn it back into a normal battery, simply use a pencil to fill in where you cut the trace.