I used to use the "mayonaise" jars in my canning, but then they broke in the hot water bath and I quit using those-so DH's Grandmother would save the small jars for jelly.. and they do make great jelly jars. But I prefer to use the Ball/Kerr jars, lids etc for safety sake now. I have not ever pressure canned so I cannot tell you on that one .. Enjoy your canning session and make it a memorable one. My DD's still tell me about all the canning sessions we had with his grandmother and laugh at some of the "incidents". LOL