Leather dust is a by-product of shoemaking process. It is similar to sawdust in that it is created when the leather is run through a band saw. Most bootblacks obtain their leather dust from shoemakers, who clean it out of their saws regularly.
Leather dust can be combined with cement to make a filling compound for filling in gouges in leather. The leather gives the compound bulk and stability, while the cement provides adhesion and pliability. See gouge repair for further information.