I have used pine shavings, cotton rags, dadant smoker fuel, hardwood leaves, combinations of all of the above and by far my favorite is pine straw. I bought two bales of pine straw at home depot, placed them in an old garbage can next to my beehives so i always have a readily available source of very dry smoker fuel. For me it works great. The trick is to get a good source of real hot pine straw coals so to speak, then pack it with dry straw, puff it till hot again and it will produce smoke for hours.