Flashlights are a key tool in your emergency-preparation kit and are worth their weight in gold in a power outage, especially during a storm. Often, batteries are allowed to remain in flashlights for several years at a time, which will eventually lead to corrosion of the battery. The corrosion is caused by the acid contained in the battery leaking out of the battery into the bottom of the flashlight, as well as the atmospheric humidity in the area in which the flashlight is stored. For inexpensive flashlights, you may be tempted to throw the flashlight away; however, for more expensive models, consider cleaning the flashlight of the battery acid rather than discarding it.
Disassemble the flashlight by unscrewing the top, bottom or both, depending on the model. Remove the battery or batteries if they are not stuck.
Remove the battery with a dowel rod and hammer or drill if the battery is stuck. If the flashlight comes apart on both ends, place a dowel rod on top of the battery and tap the end of the rod with a hammer until the battery falls out. If the flashlight disassembles on only one side, drill into the end of the battery with an electric drill. Once the bit is securely inside of the battery, rock it back and forth until the battery releases from the wall of the flashlight and remove.
Pour white vinegar into the flashlight until it is about halfway full. Thoroughly scrub the interior of the flashlight with a bottle brush to remove all acid and remaining battery pieces.
Pour out the vinegar into your sink and then thoroughly rinse the flashlight using clean water.
Dry the flashlight as much as possible using a dry towel and then allow the flashlight to air dry.