How can I discharge a battery without a Phantom?

[BlackTracer]

I returned my P2V and am awaiting the arrival of my P2V+. However I still have my extra battery. I forgot and left it fully charged and now I have no P2V to discharge it in. I have two questions:
1. Will it harm it if I leave it that way until the new one arrives hopefully in 2 weeks.
2. If it will harm it, how the heck can I discharge it to 40%?

Thanks.

 

[rfernandez]

PLUG IN A COUPLE OF TERMINALS AND PLUG IN A BULB OR SOMETHING THAT WILL WORK ON 12 VOLTS THEN TURN ON THE BATTERY