STEPS
TOOLS
Carefully cut off the top portion of the salt carton.
Gather supplies.
Use the canning lid as a template and draw a circle on the top of the piece you cut off the carton.  Center it over the metal spout.
Ready to cut out.
Carefully cut out your circles.  You will need sharp scissors for this, the cardboard is stiff,  and being on a curve it is hard to cut through.
That's it!  Place cut piece on the jar and screw on canning ring to seal.
 Empty salt carton
 Scissors
 Canning jar lid & ring (regular size)
 Pen 
 Canning jar

How to reuse salt carton lids

For years I have just recycled salt cartons after they are empty. Look at what I have been missing!