Hello, I have a pressure canner that my grandmother used years ago. Its says on the lid national pressure cooker Eau Claire Wis 18.. Im trying to find out if this cooker is suppose to have a rubber seal or is it gasketless.. Im not sure what the 18 stands for.. I would love to start using the cooker if I can make sure its safe to use.. Any information that you could give me would be appreciated. Also would like some information on how to get started canning. I loved grandmas dill pickles and would love to have the knowledge to make my own. thanks..