Well, if you were given the contents as a gift, you can return the jar to the giver in hopes that they will fill it again with something yummy and give it back to you. If you bought jars thinking you would get into food preservation and your garden wasn't the success you had hoped for and buy commercially produced product is more your style, I'll take the jars. (proof is in my garage--when aunt carol bonde moved to st. george she gave me all of her quart jars--most of them are still out there--i have to figure out Christmas gifts for everyone that can fit in a quart jar--clever packaging, yes?)
Then there are the jars that will take standard canning lid that you buy spaghetti sauce in. There's also a great jar that Mrs. Richardson's ice cream topping comes in. I think it's about 12 ounces, a great size for jam.
Anyway, I made honey-lemon jelly today. One more step to making my food
(brigham young envisioned the state of deseret reaching the ocean here in sunny so cal)