Instead of rice or buckwheat, I use sand ~ you know the kind you buy in big bags at your local hardware store. I tried lots of different fillers ie...rice, flax, etc. but I kept burning whatever I had put into the bag because I like mine really warm . So, I had some jars of sand in my sewing room for another project and I thought Hey, I'll try this and it works wonderful. No more burned smell. Works like a charm. Give it a try and see what you think.