Lavender and Wheat Heating Bag?

I have made these by sewing a rectangle with leftover fabric. Any size you want, depending where you want to use it-for the neck, feet... Leave a 3" opening (for filling) on the side seam or leave the end opened. Fill, then stitch up the opening. For the filling I used Soft Wheat Kernels & crushed dried lavender(I didn't have many flowers, so I used the leaves instead & it smells the same). I've also seen rice used instead of kernels.