It drives me crazy when I need a battery and I can’t tell if the one I’ve picked up from the box is new or used. Do you remember the batteries with the built-in tester? Those were great! Without them, I’ve had to improvise.
After picking up a bulk pack of batteries, I took 5 minutes from my day to cover the end of each with a tiny sticker. The sticker is over the tip, so it has to be removed for the battery to work. Now, if I find a battery laying around and it has a sticker on it, then I know it’s new. If not . . . .well I’d probably test it just to be sure.
The stickers that I’ve used are hole reinforcements.