Occasionally I will get a little globule of the epoxy that I use to cement the fipple and head ferrule of my whistles into the windway. Even a little bit can wreak havoc with the sound of a whistle. I used to disassemble the head (dangerous since it requires a torch to heat the head ferrule to break the glue bond), clean it out, then re-cement.
Recently, I figured out a very simple tool to do the job. I bent a fine coping saw blade back and forth until it broke in half right in the middle. This is thin enough to easily fit into the windway. I use the half that has the teeth oriented so they cut in the “pull” direction-- just insert the blade in the windway, press it gently against the glue or other obstruction, and pull back. In a couple of passes, the windway is clean as a ,well, whistle!
It ought to work equally well for removing extraneous bits of plastic when tweaking Generaton type whistles.
Good suggestion Paul. If you want a cleaner cut you can use a rotary tool with a small cut off blade. I recently used a coping saw blade and rotary tool to make a click spring for a clock mechanism I was fixing. I was able to cut the little tabs and fit it to the clock with no trouble. It worked great.
Ron
Paul, mind if I ask why you’ve chosen to use a glued in block rather than a pressure fit or pinned block? Just curious.
Loren
tell him nothing…he’ll use the technique for his confounded re…or…s.
I shoot for pretty much of a pressure fit, but I like to use a small dab of epoxy for insurance. Sometimes, if a block ends up really snug, I omit the epoxy altogether. It really doesn’t stick all that well on the Delrin, and I can easily knock the block out if a whistle needs revoicing.
Are you kidding? I could learn HUGE amounts of stuff from the Von Huene workshop. These folks make some of the most superb instruments in the world. Really. In fact, now that I have an inside internet bud at V.H., I may wheedle and beg to go spend a day there…
i guess you’re right…no harm in learning how to improve one’s skills. 
Paul, I’ve got about 500 pieces of Boxwood to Gun Drill, now would be the perfect time for you to visit and help me with this oh so glamourous task!
Too bad you missed out on all the fun of turning them from square to round, and then facing 'em
Loren
My wife calls this step “making sticks”… Actually, with more figured woods this step is pretty exciting since this is when you first see the graining pattern that will be on the whistle.
Have you turned any really tiny bits for plugging holes yet? Around the shop it’s called “turning toothpicks”.
Yeah, we’ve got some really nice Kingwood and older Brazilian Rosewood that are fun to turn, but I don’t really get excited till we start oiling and buffing the finish sanded pieces, when you can really see the depth of the grain patterns, that’s what gives me the juice - polishing some beautiful piece of wood till it looks like a piece of lacqued custom furniture, that just happens to sound amazing too 
Loren