<In general, how do you decide whether to use an old jar for canning if it appears to be in good condition? >

My criteria are (1) if it has collectible value don't use it and save it for dry storage, (2) if not, and if the newer 2 piece lids and bands fit use it for BWB only, (3) if they don't fit and you really have to use it and with the rubber seals and zinc lids use it only for highly acidifed foods (but pickles look really ugly in the grey jars, same for the blue ones). Better yet, clean it up really well and use it only for dry storage. :)

Dave

Don't know what is collectible. I wish I knew a collector. It is tedious trying to look them up on the internet. I've got enough oddball ones that I wish someone could have a look them at to tell me what is collectible, and what is "a dime a dozen" despite their age and, to me, coolness.

But freezer jars--can they take the heat?

Freezer is printed in the glass of the jar?! That is confusing because they sound like very old canning jars to me. I have some zinc lids and actually bought some new rings for them at an Amish store once, those work for canning in BWB just fine. I like older jars because they used to make them so much thicker, I have never had old ones break, just new ones because they are so thin if they clank together they are more likely to crack.