Lift the battery cover from notch at the top of the cover.
Remove the battery by lifting up from the notch at the bottom edge of the battery.
Clean any debris off the gold contacts on both the battery and the device.
To re-insert the battery, ensure the metal contacts on the battery and device are aligned on the top edge of the compartment, and then press the battery into place.
Reattach the battery cover, pressing firmly around the edge of the battery cover.
The battery contacts have now been cleaned.