Do you mean you are re-using the screw on bands, but not the lids? If so I do not know why you are having prolems with the jars sealing. I rarely have one that does not seal. Are you filling the jars too full? Are you wiping the lip of the jar clean before you put on the lids and screw tops? When you fill your canner do you let it vent for 2 or 3 minutes before you close the pep **** and start to build up the pressure?