FLCC> Rust flakes inside steel frame

[Jack Loveless]

Dear FLCCers,
  I recently bought a new-old-stock steel frame which is very nice
except for one minor flaw: there are rust flakes that float around in
the top tube.   The frame is constructed such that the top tube is
sealed - the only holes in it are internal brake cable stops - so
getting the rust out has proven pretty tricky.  I have tried 1)
fitting a vacuum around one of the holes to suck the rust out, 2)
using compressed air to jettison the flakes away, and 3) inserting a
waxed piece of yarn inside one cable hole with hopes of attracting the
rust and luring it out.  No luck.  I'm hoping to find a home-brew
remedy before taking the frame to somewhere that might have a smaller
diameter, high power vacuum.  Has anyone encountered this problem
before, and if so, could you share any tips?  I'm eagerly anticipating
building up the bike but would like to solve this problem before doing
so.

Many thanks,
Jack Loveless