Find a scrap of fabric that’s at least a quarter-inch wider than the ring on all sides; the piece that I’m using for this jar is 4.5″ square.
Center the fabric on top of the Mason jar, and screw the ring onto the jar right over the fabric. It’ll be a little snug, but it will screw on. For a food item or a canned good, the fabric will go on top of the lid, but if you’re giving a dry good such as my homemade laundry soap, especially if it smells nice (which it does!), then consider excluding a lid altogether, since just the ring and the fabric will keep the insides contained.
