Remove the plastic plug from the lid with a knife and trace around the opening. Cut a cardboard insert to fit inside the opening. Test the cardboard to check it fits. It should just squeeze through. Cut 1-2 pieces of foam to match.
Cut out the design area on the template sheet and pin into position over the embroidery.
Use a disappear-ing pen to mark the outside edge of the template.
Thread up with heavy weight Nymo thread or dental floss and stitch 1 cm or 3/8" outside the marked circle. This distance is greater than I usually use because we will be mounting the embroidery over 2 layers of foam.
Cut 1cm or 3/8" from the gathering stitches. Make sure not to cut the gathering thread.
Place the embroidered piece face down on a towel pad and lay the 2 layers of foam (I cut one of the foam circles slightly smaller and placed it on top of the larger one!) and then the cardboard insert on top.
Push down firmly in the middle of the insert with 2 fingers (you might want to ask someone to help you). Pull firmly on the thread to gather the embroidery around the insert.
Sometimes a second gathering row either inside or outside the first row can give a tighter lacing to the embroidery.
Remove the plastic stopper from the lid using a knife.
Cut a piece of foam to fit into the plastic stopper - this will hide the back of the insert.
Stick a piece of double-sided foam mounting tape to the foam circle.
Centre the mounted embroidery onto the centre of the foam and press firmly.
Insert the embroidery into the lid of the jar and replace the plastic stopper.