Acetonitrile is one of the most useful solvents for chemical reactions, as well as being widely used in HPLC.  However it is becoming in short supply.  This is partly because it is produced as a by-product in the manufacture of acrylonitrile, and the demand for this commodity is reducing, whereas demand for acetonitrile is increasing.  (Chem and Eng News, Nov 24th, 2008, p27).

So maybe now is the time to think about the possibilities of recycling waste acetonitrile – after all most of the world supplies are, I am sure, not consumed in any reaction, but remain in some effluent stream, if only they can be removed, recovered, recycled and purified.  Reuse, of course is better than recycle.