I learned the wax sealing as a kid helping my mom. Yeah, the little bit of mold that sometimes was found, you scooped it off with a little of the "good jelly" below it and ate the rest. Not a big deal. We only did the full sugar jelly making then. Us kids would go and scrounge and find the wild grape vines and get the grapes and bring them home for mom to make the jelly. Got apples from the tree, cut out the wormy stuff, made apple sauce and apple jelly. Mint that grew along the creek or wetter spots... Blackberries and raspberries that grew wild. We did the collecting, mom did the making and we had jelly all winter for pbj sandwiches.
I have hundreds of the old bail top glass jars . Only had to buy the rubber rings. You can still buy them and I intend to start using them again next year, if I run out of the regular jars and lids. Once the seal is done and the jar is cool to store, you flip the bail off. Any problems, or spoiling of the contents, the glass lid is loose. You toss the contents.
I do like them for storing stuff on the shelves though, they look nice.
Yeah, I know there are going to be many that will tell me that I am crazy. I do not use the zinc lids with the jar rubber. I don't like not being able to see that the rubber is truly in the right place although have done a few with my grandmother like that when she was showing me how it was done "in the olden days" LOL.
I should have enough to not need the bail lid jars though. Having inherited from so many, plus keeping any jars that will use a standard size jar ring and lid, and even reusing smaller store bought type jelly jars and their own lids, I have enough to last forever. If you sell any, then they have to be new jars and lids. That's only safe and smart.