Unfortunately, this sounds like static electricity.
Leica suggests spraying anti-static spray in the chamber (!).  You could
also ground the metal in the chamber using metal wire touching something
metal outside the chamber (the Russian post-doc solution, very clever).  We
keep 100% EtOH in a small container (about 100 ml) in the back of the
chamber to reduce static, which I learned from a long ago histonet post, so
I have no idea why it works.
Otherwise, buy an anti-static brush, which I hear exists, but have never
seen.

Emily
-- 
the velocity of time turns her voice into sugar water
http://www.youtube.com/watch?v=jNA6zzoObxg
_______________________________________________
Histonet mailing list
Histonet@lists.utsouthwestern.edu
http://lists.utsouthwestern.edu/mailman/listinfo/histonet