Batteries get stuck when corrosion leaks or they swell due to age or heat. You can remove them by shaking, pounding, or using solution of baking soda and vinegar, or WD40.
Note you can prevent this by changing batteries on regular basis and keep them out of the extreme heat. Do not use a screwdriver or other sharp tool as could cause puncture.
Even with the advent of rechargeable flashlights that use permanent Lithium-ion batteries, many flashlights still use old school size AA zinc-carbon batteries. The latter are removable – a good thing – but tend to leak, corrode, swell and get stuck inside the flashlight if you forget to remove them at the right time when they die.
Removing dead, stuck batteries can be a real ordeal because of the risk of spilling the unsightly paste on yourself or ruin your flashlight in the process.
The easiest and safest method involves pouring a solution of baking soda and vinegar into the battery compartment.
Step 1: Open The Rear Cover or Remove the Headpiece
This is going to depend on how your flashlight was designed. Some flashlights will take batteries from the rear, meaning they can only be removed from that opening. Other flashlights are designed to open in the front by removing the headpiece.
Step 2: Pour The Baking Soda + Vinegar Solution in The Battery Holder
The vinegar/baking soda solution works like magic – it will loosen and dislodge the corroded parts in the compartment to free the batteries. Remember that the paste exuding from the dead batteries is mostly acidic, and baking soda/vinegar mix is just the right neutralizing agent for it.
Fill 1 tablespoon with vinegar and a tablespoonful of baking soda in the battery compartment. Not only will it help loosen the stuck parts, but also reduce the toxicity signature of the oozing paste if the batteries have been there for so long or have been badly damaged.
Step 3: Cover One End with A Dry Tin Foil
The solution is still inside the flashlight, so you need to seal the open end – whether rear or headpiece – of the battery compartment with a clean tin foil. The foil will help put in control the discharge oozing from the stuck batteries.
Also, the tin foil will prevent the solution from spilling on other exterior parts of the torch or yourself.
Step 4: Gently Shake the Battery Compartment
Ensure that the tin foil you used to cover the open end is closed tightly not to spill the solution.
Now, shake the battery holder gently enough to disturb the solution evenly and dislodge the stubborn parts that may be still stuck on the walls of the battery compartment.
The acidic liquid is toxic and can burn or cause irritation on the skin if allowed to spill out. Wear some rubber gloves and handle the compartment with care.
Step 5: Lastly, Open The Cover and Let the Solution and Materials Pour Out
Lastly and more importantly, you need to carefully open the cover foil and let the mixture pour out of the compartment. Empty the mixture in somewhere safe where it won’t end up on grass, open surfaces, or drinking water.
Check if all the batteries and their fragments have come out. If not, proceed to tap harder on the body of the flashlight to make weaken the grip. You can as well push a stick between the batteries and the wall of the compartment to dislodge the stuck parts. Even better, you can let the holder stand for a few minutes for the corrosion to dissolve completely before trying to force the batteries out. Whatever you do, make sure you don’t come into contact with the solution.
After the dead batteries come out of the holder, clean the interior with warm water and a soft cloth. Rinse the soft cloth, dry it, then wipe the holder dry. Leave the holder in the sun or near the heater to dry. Thereafter, return the headpiece if you removed it and add new batteries. You have just reclaimed your flashlight!
Be careful not to pull out or break the contact terminals and wires soldered on the headpiece or the cover at the rear. If time allows, use a clean toothbrush and detergent to scrub the interior of the holder and give it a fresh smell. The smell of vinegar tends to stick on surfaces for long, so this sounds like a must-do. Finish by rinsing the holder thoroughly to remove the residue, then hang it to air-dry.
There are multiple ways to remove stuck batteries including shaking, hammering, and baking soda solution. Another option is tossing old one in trash and buying a new one as they are not that expensive.