Ian,
 
Flex is a patented dehydrating reagent sold by Richard-Allan Scientific and
is specifically designed for processing and staining of histological and
cytological tissue specimens.  It is a blend of isopropyl and methyl alcohol
available in concentrations of 80%, 95%, and 100%.
 
Clarifier I is a reagent containing ethyl, isopropyl, methyl alcohols and
glacial acetic acid designed to eliminate background staining.
 
Like you I was skeptical about the three one minute rinses in the 100%
dehydrant but have had excellent results using this procedure.  I am careful
to thoroughly drain and blot the staining racks between changes, am strict
about rotating solutions and always use an appropriate volume.
 
Should you care to contact the company for additional information:
 
Richard-Allan Scientific
225 Parsons Street
Kalamazoo, MI  49007
(800) 522-7270
Fax:  (616) 345-3577
 
Joan
Regeneration Technologies, Inc.