When my mother was still around, any time I tried to open a jar after she'd gotten to it, I would destroy my hands and still not be able to get it open. I could wreck tendons, give myself blisters, try all the tricks mentioned in this thread, and those lids wouldn't budge. It was like she found a way to weld metal to glass with her bare hands. By comparison, opening the factory seal was no effort at all.