1. Old batteries
A battery left in a device for years can leak as its chemistry breaks down, even when the device is switched off. Replace batteries before they reach their expiry date.
2. Running flat in a device
Leaving a device on until its batteries are completely flat can cause leaks, especially with cheap alkaline cells. Remove batteries from anything you won’t use for months.
3. Mixing and reversing
Mixing old and new cells, or fitting one the wrong way round, can cause leaks. Check the + and − marks every time you change batteries.
4. Heat and damage
Heat speeds up leaking, so keep batteries out of hot cars and away from radiators. A dented or damaged cell is more likely to leak, so replace it straight away.