Tape those suckers off when you store them somewhere or you may have a nasty fire on your hands. Both terminals so close together makes for an easy short if it finds the right bit of metal somewhere.
Also one thing I learned recently: may 8v batteries have 6 tiny rod batteries inside of 1.5v. like AAAA or even smaller.
Sorry meant to say "many 9v batteries". I can't edit posts in this mobile app :(