tecno4

Many a time I’ve managed to get my hands on some electronic gizmo only to find that the battery compartment totally corroded. It’s usually one of the main reasons I think that people throw toys and whatever else takes batteries away
The corrosion is caused by potassium hydroxide which can leak out of alkaline batteries (these are the usual types of batteries you put inside toys etc). All batteries discharge, either through use or just slowly through the production of hydrogen gas which forms pressure in the battery. Eventually that pressure will find a way out through a seal or as the battery ages, through corrosion or rust in the outer shell.