There is a button combination for deep sleep mode as listed here -
Extra Button Functions
OK, copied here, but that link is the official info:
Deep Sleep Mode
If you are transporting your Amulet Voice Remote, buttons may be accidentally pressed in transit, or the remote may tilt enough to activate the microphone. If either occurs for an extended time, the battery will run down.
To avoid this, you can put the remote into a deep sleep. Press and hold the DVD Menu and TV Power buttons simultaneously, and the Amulet Logo will flash green twice. The remote is now asleep, and will ignore button presses and movement.
To wake it again, press the green Media Center start button in the center of the remote, or briefly connect the charging cable to a USB port.
We hope to bring out a cradle in the future.