Hi Mary Ann - we use 5% Trichloracetic Acid in 10% NBF!! 
Another good one to try is PERENYI'S Fluid (10% Nitric Acid :40ml. + Absolute Alc.:30 ml + 0.5% Chromic Acid :30 ml. 
Hope one of these works for you.......NAIR is another consideration!!
Cheers, Bruce in OZ! 

BRUCE ABALOZ
HISTOLOGIST		      
DEPARTMENT of ZOOLOGY	           *  ph:    +61 3 93446282
The UNIVERSITY of MELBOURNE        *  fax:   +61 3 93447909 
Parkville, Victoria.3052           *  email: b.abaloz@zoology.unimelb.edu.au                                                                       
AUSTRALIA.
          OPEN THE MIND;STRENGHTHEN THE BODY;FORTIFY THE SPIRIT!!                 
                    DANCE, LIKE NO - ONE'S WATCHING!!
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