Doing a Drop Test
1
Get the battery you suspect is dead. If you have have a device that harbors multiple batteries, it would be a good idea to test all of them. Keep in mind that this method only works for alkaline batteries, more specifically the AA and AAA models.
2
Hold the battery with the negative terminal (flat side) facing down. Preferably have it held one or two inches above a flat surface, such as a table.
3
Drop the battery. If it bounces and falls over, then you can assume that it is dead. Dead alkaline batteries have a gas inside that account for this bouncing. If your battery doesn't bounce, or even stands up, then it still has its juice!
Why A Dead Alkaline Battery Bounces!