I like to store broths, soups, nut butters and sauces in canning jars, but the standard lids with rings have always frustrated me.
Maybe I'm the only mom out there that didn't know that these existed, but I recently discovered that they make plastic lids for jars. You can find these in Walmart (I think they even have a generic brand) or any general store and even Amazon. They're usually in the kitchen section right beside the canning jars.
These are much more convenient than the standard canning metal jars and bands. These don't rust. They are one piece (hallelujah!). They are easy to wash.
They come in two sizes (regular and wide mouth), so be sure that you pick up the right size to match your jars.
I'm kicking myself for not finding these sooner.