Sawdust comes from the cutting, sawing or sanding of wood, leaving small particles behind. Once collected, these particles are considered sawdust. Sawdust has several uses in pyrotechnics. Sawdust is used in certain smoke mixes as well as primes. The most common use for sawdust is in the form of wood meal , which is used in Veline's superprime.
The most useful types of sawdust are of soft woods like pine and willow. It's relatively easy to produce sawdust or even wood meal by using a belt sander or any other type of sanding tool, even by hand. However, the latter will take quite a while to produce an amount that is useable.