plant tissue grinding equipment

[Michelle.Gleeson at SMTPGWY.AGRIC.NSW.GOV.AU]

     Hi bionetters,
        I'd like to hear people's recommendations on equipment for grinding 
     plant samples.  I extract viroid RNA from leaves mainly, sometimes 
     bark.  I have tried two blade type machines (Ultra Turrax and 
     Polytron), but these do not give small enough leaf particles and are 
     hard to clean between samples.  It would be best if the equipment 
     could be cleaned with sodium hypochlorite.  A Waring blender did not 
     work either.  Mortar and pestle gives the required results eventually, 
     but I want to process large numbers of samples - painful!  The tissue 
     needs to be a thin paste when ground with buffer, with none or few 
     recognisable leaf particles left.  I've heard good stories about a 
     "Klecko" machine which uses ball bearings, but we'd need to import one 
     into Australia to even try it, I think (suppliers?, any in Oz?).  Any 
     hints, recommendations etc gratefully accepted.
     
     Thanks in advance
     Michelle Gleeson
     NSW Agriculture Biological and Chemical Research Institute
     Sydney, Australia
     gleesom at agric.nsw.gov.au