Inspired by recent post, how can I open these jars that's been sealed for 60 years?

No, I cant pull the green rubber, because the seal is so old and the rubber has dried. I've tried with warm water and steam, but I belive that it isn't working due to the rubber being dry? It might be that I am a chicken that's afraid of the jars exploding too, so maybe I didn't do it properly? Can somebody explain the methods in detail?😅

No, I cant pull the green rubber, because the seal is so old and the rubber has dried. I've tried with warm water and steam, but I belive that it isn't working due to the rubber being dry? It might be that I am a chicken that's afraid of the jars exploding too, so maybe I didn't do it properly? Can somebody explain the methods in detail?😅