Turn an AAA battery into an AA battery instantly
Your wireless mouse has died and you’re on deadline. Or you kid’s toy stopped working and they’re not happy.
If you’re out of AA batteries, did you know you can use a smaller AAA battery by folding up a small bit of tin foil and inserting it on one of the ends?
It totally works since AA and AAA batteries carry the same amount of voltage... More here.
Some very useful hacks on this page, especially the battery one.