Everyone here has bought a battery at sometime or another, and we're all guilty of throwing these little guys in the trash.
These are the little covers/caps that they put on the terminals to protect against unintended metal/electrical contacts. When ever you replace a battery, you instinctively toss these away, along with the carrying handle, plastic wraping,...and dare I say...reciept. Next time, toss one in the top of your tool box.
Next time you need to store your vehicle/ATV/lawnmower, or perform a repair on your daily driver...nothing beats it as a improvised insulator.
I keep mine in the glove box
