The other day I ran across 4 AA alkaline batteries in a drawer next to our coffee maker. There was no way to tell whether they were good or not because I don’t have a battery tester. Turns out, you don’t necessarily need a battery tester, just a hard surface.
Bad batteries will bounce on a hard surface if they’re dropped from 10″ or so. Good batteries on the other hand, will land with a thud.
Science classes have tested the theory for years and you can find many videos on YouTube recorded by scientists who claim they find it to be true. They found once an alkaline battery discharges, it changes the chemistry inside. in a paper from the Journal of Materials Chemistry, scientists explained that zinc inside the battery slowly oxidizes as it is used. Some experiments where scientists drilled and cut open new and old batteries to come up with their findings.
Princeton researchers; however, say the claims are not entirely accurate and that batteries with some life left in them will bounce just as high as dead batteries. You can read their report here and a giph of their experiment here.
So while you should be able to easily determine if a battery has never been used before, batteries that have some bounce may have a little life left.