Here is what I used :
2 pounds of lentils and 1/4 cup of dried lavender
2 18x8 strips of any fabric
With your sewing machine, sew your strips of fabric together on all 3 sides (two long and one short) with the fabric inside out. Sew the 4th short side half way. Turn the fabric right side out and through the un-sewn opening fill the bag with the beans and lavender. Hand sew the rest of the 4th side.
This is perfect for headaches, back aches, neck aches... well pretty much any ache you can think of. Microwave it for a couple of minutes for heat or store it in the freezer for cold.
Now I can throw my old unscented rice bag away because I have a delicious smelling Star Wars bean bag!