Cut the fabric into a 20-by-14 inch rectangle. Fold it in half lengthwise with the right sides together to form a long tube shape.
Sew together the long edge and one short edge with a sewing machine. Leave a 1/2-inch seam allowance,
Turn the tube right side out and iron it flat. Set the tube aside.
Mix the filler in a plastic bowl and use a plastic spoon. Plastic tools will not retain the scent and transfer it to another batch. First, pour enough dry white rice, clean cherry pits, buckwheat hulls, dried feed corn, flax seed, barley or beans into the fabric tube to measure the correct amount needed to fill it. Make it firm enough to be comfortable, but flexible enough to wrap around the neck. Pour filler into the bowl and add 1 to 2 tbsp of three different dried herbs and 30 drops of essential oils and mix well.
Fill the fabric tube with the filler material. Turn the raw edge of the tube under to the inside about 1/4 inch and hand stitch it shut.
Place the tube in the microwave on high for 1 to 3 minutes. To be safe, put a cup of water in with it so the dried materials will be less likely to catch on fire. Carefully remove from the microwave and shake to distribute the heat so it will not burn skin. Apply to the affected area of the body.