Something about the contents of a jar that is so reluctant to open - just so it wasn't swollen and shut!

I have one of those rubber-lined multi-size lid grip things that I bought while I was in the throes of PMR - weak hands were a feature of it; I use a pliers on small bottle screw tops if it won't open. I suppose the "pierce the lid" tip would work - just such a hazard to work around that now sharp metal. Rubber gloves work. I have a flat thin rubber disk that I think was meant as a sink stopper but that also works on some jars. That doorway method sounds effective but I'd be afraid of leaving a mark on the wood.