AA meltdown

battery leakage
Let this be a les­son to you. Do not store elec­tron­ics with the bat­tery inside.

My mini­disc recorder had a bat­tery leak and now it is bro­ken.

If you plan on stor­ing some­thing for a while, remove the bat­tery before plac­ing in stor­age.

RTFM, my friends. RTFM. And, also, fol­low your own advice.