Don't know if anyone else has found another way to clean out the Finnigan H-
Device reactors yet. Although not very elegant, the following physical
procedure works.

Some history:

The H-device uses Cr powder at high temperature to produce hydrogen gas
from liquids. The loose chromium powder is poured into the quartz reactor
but forms a more coherent oxide once the reactor is used up and can't be
poured out so that one is forced to buy a new reactor ($183) after 100-200
samples. Cr2O3 is not readily dissolved or reduced. However, it does come
apart with a little scraping.

Cleaning Procedure:

1. Drill out a hole by hand through the Cr2O3 using a long, thin bit that
will fit into the wider end of the reactor.

2. Attach a thin metal cable (1.5mm) or twisted/braided wire to a drill and
slip the cable into the reactor.

3. Drill away the chromium. The cable should bend at the tip due to its
spinning and scrape the walls of the reactor. This works to get rid of 75%
of the chromium but takes about an hour. Moderate drill speeds seem to work
better. A little Cr2O3 is left near the wide tube end.

4. Use a thin solid wire (24 gauge) and bend it slightly near the tip.
Insert it into the wide tube end of the reactor and push it all the way up
against the narrow tube end so that the tip gets bent to a right angle. Now
this can be used to scrape off the remaining Cr using a drill or by hand.