I always buy the flat lids new. But like the idea of saving used ones for beans and pastas. I will try to do that from now on. I have started saving small store bought jars and lids for jellies and jams, and they really do seal. I am so glad I learned of this. I just haven't gotten the nerve to seal them in the microwave yet. good luck. I just finished 30lbs of pickled garlic. I am taking a break for a week or two.