This can save you a lot of money!
Have you ever needed a 1.5v battery for your alarm clock, laser pointer, calculators etc.? Instead of buying expensive batteries in Walmart or Best Buy, you can easily save around $40 by simply hacking an A23 12v battery.
The video below explains a step by step how to turn the 12v battery into eight small 1.5v batteries.
*Update: From what we have heard this hack works better with Duracell or Energizer batteries. To avoid any danger it is recommended to use the small batteries for appliances with a low energy consumption. Do not use the batteries on expensive devices since there is a risk of leakage that would damage the device and your health.