The other day my Blu-Ray remote control ceased to function. I had just changed the batteries a few weeks before but i opened the cover anyway to see what was happening. One of the Kirkland (Costco) AAA batteries (there were two inside) had leaked white powder into the compartment.
I immediately removed them and went to my battery storage container to retrieve new ones. To my surprise, several of the ones in my container had leaked and gotten the white substance all over the others.
I threw them away and bought new AAA batteries. It got me to wondering about the cause of this annoying problem. As the batteries generate power through use or self discharge, a liquid electrolyte breaks down, releasing hydrogen gas causing pressure within its casing.
If the case breaks down it can rupture the seals and cause the leak. The break down can be from bad storage, like extreme heat, cold, dampness, or just being cheap and faulty in manufacturing. The liquid electrolyte is potassium hydroxide which, when touching the open air, reacts with carbon dioxide to form potassium carbonate – the white powder.
Careful handling and touching the residue and you should certainly wash your hand well afterwards. Make sure to clean the inside of the battery compartment with a q-tip soaked in lemon juice or distilled white vinegar to removes all the residue. You can then remove all the white stuff with an old toothbrush.
Alkaline batteries leak because they are made to leak. There is no way to prevent their leakage other than to use and discharge them very quickly. One day to a few weeks to complete discharge will generally avoid leakage. The case of an alkaline battery is the negative electrode and it is consumed as the battery is discharged so it will develop weak spots and leak. Especially when discharged slowly or in storage.