[meteorite-list] Cleaning question

[James Cheshire]

Hi everyone, lately I've been sifting through Nantan debris and
sorting out the remnants of graphite, schreibersite and troilite
inclusions. They are unfortunately coated in iron oxide/hydroxide from
the associated meteoric iron. Can anyone suggest how I might clean
this off without damaging the underlying minerals? The fragments are
all very small, so cleaning by hand is out.

James