Laurie and I have been using these canning lids for seven years now. They are as advertised. We've used them over and over for water bath, pressure canning, and even sealing of jars for dry goods using our jar vacuum sealer attachment.
We've canned vegetables, fruit and all kinds of meat and fish.
We don't have any trouble with them sealing, in fact the last few years these lids do even better than metal lids because the metal lids have gotten so thin. Its important to follow the directions on the box and it does require "some" experimentation with lid tightening etc but over all they seal just fine and yes, you can use them over and over. To date we have not thrown any away.
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