Like Steve said above, I've heard that cyanide is a common practice, but haven't seen any actual publications on the web. I imagine collectors and vendors want to keep that out of the public eye. Google yields tens of thousands of forum entries of Naso cyanide, but not many actual publications.
One trick that works for me with picky fish is to thaw out frozen fish food and mix it with pellets, flakes (the frozen food along with a few drops of garlic extract and selcon will moisten the dry food), and wrap all of that in seaweed (like a small burrito about the size of a flattened cigar). Most picky fish will come to investigate it on the clip, and when the pick at it, a little frozen, a little pellet, and a little flake will drift out. More than likely, they will eat something in there. It also helps acclimate fish to different food types. If the go after mysis, they are likely to get a pellet along with it, etc....