Many alkaline batteries have a tendency to leak a corrosive acid. Might not have the best description of the corrosive. However, many alkaline batteries have a tendency to leak and the substance they leak corrodes whatever appliance, toy, tool contains the battery. I have not had any Staples battery leak. It could be that I have just have not used enough to get one to leak. However, I have been quite happy that I have not had any that leak.