I'll try baking the rice when I make another. I was going to put lavender or some potpourri in it, but I was hesitant as some scents bother me. I'll try something though.
I used a very long tube sock, but never thought of a cover. Good idea. I had to buy an entire pack of socks, so I've got several left. And the really nice thing about these, besides that they work so well, is that they're very inexpensive to make!