I still have some of my great-grandmother's quart jars like this (GEM jars from Canada, similar in age to the jars you have). I mostly use these heirlooms to store dry goods rather than for canning or preserves. Jars this old should still be useable for canning if the necks and glass tops are in excellent condition with no chips or cracks. The rubber sealing rings become brittle with age, and aren't as reliable as today's snap-lids, so for canning I would recommend trying to find appropriately sized modern snap-lids instead of the glass tops/sealing rings, and avoid using these for pressure-canning. I don't know what kind of price they would sell for, perhaps as a collectible, but if you have a use for them, I would say keep them.

The glass tops shown in your photo can not be used on those jars without the missing pieces. These glass tops are not screwed on, but held down by a toggle bail made of heavy wire. Sealing was not as reliable as later developments.

I can't tell if the tops of these jars have screw threads. If those do have screw threads, then I recommend to use a flat 'pop' top with a screw ring. The flat tops are slightly domed and have an elastomer seal bonded to the top. When sealed, and a vacuum developed, the dome snaps down.

Those rubber rings were normally used with a substantial screw-on lid. (I don't see any in the photo.) The lid may be zinc coated and the inside of the lid covered with a glassy like ceramic, maybe porcelain. The lid compressed the sealing ring against the lower flange of the jar top. This was not considered the best since there was a space between the lid and jar where the contents could collect if the jar was inverted even momentarily. This design was opened by pulling the rubber ring out; That's what the tab on the ring is for. If one has a super thumb-finger grip, unsealing can be done by hand. Most women kept a pair of pliers handy to unseal these jars. Once the rubber ring has been removed, the lid easily unscrews.

If the jar's top surface is unblemished, these could yet be used for canning. However, these are old jars and may have value, enough so that you may wish to protect them for collection purposes. If used for canning, only a screw ring with flat (slightly domed) lid is recommended.

I have several of those old blue jars and because they are relatively common they are worth a few dollars each, but unless you have something rare, they aren't particularly valuable, at least as vintage/antique items go

If the rims are intact and unchipped they can still be used for canning, although I don't. The rims are wider and sometimes uneven, and I have a couple that don't give me a reliable seal, although they appear unscathed. That's fine with me, as I said, I like the way they look. I use them for storage of things like dehydrated peppers or apple slices, or for pantry staples like beans, rice or lentils. They look interesting on the shelf and keep those partial bags of legumes from spilling from their bags.

My daughters both have some on their counters with hand sanitizer in them, they bought the pump dispenser tops from somewhere. Crafting with canning jars is a big thing, I guess, and they have everything from the pump dispenser tops to lids with straws so you can use your canning jar as a water bottle.

Enjoy yours, I like to just see them on my shelves.

Annie

The OP posted this twice or at least a similar post on the same day. If interested you might want to find and read it.

maifleur, I thought I'd read this recently, but couldn't find it so assumed I was just wrong.

Annie