Book 27, Question 74
What is the crusty white stuff on old batteries?
When an old alkaline battery leaks, the liquid inside reacts with air and dries into crusty white crystals.
The crystals can irritate skin and eyes. If you ever see white crust on a battery, do not touch it. Tell a grown-up, who can wear gloves, remove it, and dispose of the battery properly. Taking batteries out of devices that are not used for a long time prevents leaks.