Two 9-volt batteries together is dangerous?

Question

In the winter, I stick two 9-volt batteries to each other. (positive side to positive side) Then I put a pair in each outside pocket of my ski-gloves. They quickly warm up and they're cheaper than those warm packs because I only need 4 9-volts and they're reusable. I can use them the whole winter long. But out of fear I usually throw them away when the winter is over.

Is it dangerous to do what I do, could my warming battery sticks harm me?

Do they actually use energy when stuck together or just pass it back and forth?

Anyone else do this?

Answer 1

No that is extremely dangerous. For one, that could shock you, for another they can overheat differently, and dangerously fast. I would recommend you spend the extra on heating packs.

Answer 2

By connecting them in parallel (+ to +) you simply create another 9V battery, but which can provide more current.  However, since nothing is connected to them, the only way to have heat is if one of them is "shorted".  Make sure that when you put them in your glove you don't create by accident any shorts. A short could be a fire hazard and can even make a battery to explode.