ideally something less "chemical/plasticy"
i though flower would probably be more pleasing to the nose
i do burn wood with paint and other finishes along with around 5% mdf 5% chipboard[worktop/ sheet/ flooring/laminate]
anything with a finish i keep to a small amount to avoid the plasticy wiff you can get
Even flour dust, when mixed with air in the right proportions is explosive. I don't think sawdust is particularly explosive though. There's far too many large particles to allow it . Very fine wood dust (as in sanding dust) can be explosive, when mixed with just the right amount of air (but the proportions of each have to be within a narrow ratio.
I think coal fired power stations use finely ground coal as fuel - fluidised bed is the tech term. Spendy though I am sure. Or you could inject a sawdust/air mixture in and burn that, bet that would give off some heat....
Anyone see Mythbusters on Quest last night? It was a somewhat contrived situation, but they certainly made quite an impressive fireball from sawdust...