I need some advice. Earlier in the summer I made strawberry jam, which I put in glasses... you know the ones our mom's and grandmom's used. They have a glass lid and there's a rubber band around the top, then you close them with a metal thingy. They look like some of these here:
https://www.google.com/images?q=henk...g&ved=0CB0QsAQ

Well, I simply can't open it. Would it help to put it in a bowl with boiling water or what?

Hope someone has an idea. Thank you!