Thanks for the advice, guys. I could do the tuning and gapping if needed, I've done it on a couple of concertina reeds, but those are dismountable, disassembleable and big enough to see. These Huang ones are spot-welded to the reed plate and tiny, however. One slip and goodbye. When I do do it, I'll tape over the holes so that I know exactly what isn't working and mark the assembly before tearing it apart.

As for cleaning, I have all sorts of solvents, acids like phosphoric and gun blue and the stuff that they paint aeroplane scratches with, compressed air(Oh NO), and steam. Then I hear that water is best.
The universal solvent.   Thanks, Chris.