>>>My wife, after checking with the local farm extension agent, said that new, stored lids shouldn’t be used if they are over two years old. Something about the seals dry out?
Is this correct or just BS?<<<
Actually, I think it is somewhere in between. (Remember they have to be to the ‘official’ exact letter with anything they say.) The boiling water treatment before use serves to ‘rejuvenate’ them pretty much.
The seal material does not dry up and crack like it once did. I typically keep at least a year ahead of my needs (about 60-80 cases annually depending on needs)
As far as re-using - What really happens is that it takes a ‘set’ from the indentation from the jar, making the seal thinner where it contacts the jar. While not ‘officially’ condoned, I have done it for years with no more failures than from new lids.
I seem to remember a real shortage of lids many years ago and we were going to out of the way places to find them. That taught us to keep at least a one year supply ahead. As far as shelf life of new lids go we have no way of knowing how long those lids sat in a warehouse before being purchased. ..