Battery corrosion is a direct result of a battery acid leak. Assuming the batteries you’re using were manufactured properly, a leak generally arises from damage or mishandling. Obviously, if you crack a battery against a solid kitchen counter, it will probably start leaking, but batteries can also be damaged in quieter, subtler ways.
One of a battery’s mortal enemies is extreme hot and cold temperatures. A battery’s casing is designed to withstand both modest hot and cold, but prolonged exposure to high levels of either can warp the casing and allow the acid to leak out. For both the batteries and the gadgets you use them in, keep them in an even-temperature location, out of direct sunlight or vent exposure. Additionally, if you have a toy or gadget that you’re not actively using and won’t be for a while, you should take the batteries out of it. It’s bad enough when a battery starts leaking on its own, but if it leaks in a gadget, the gadget will also be in trouble.
In the specific case of toys, try not to keep them all in a bin if possible, as it’s much harder to monitor for corrosion until it’s already too late.
