Mouse skin (fixed for 4h in 10% BNF then stored in PBS) was processed
according to our ususal procedure:
70% ETOH 30m
80% ETOH 30m
95% ETOH 30m x 2
100% ETOH 45m x 2
Clear-Rite 3 45m x 3
paraffin 1h
paraffin 3h

The tissue coming out of the processing cycle was not infiltrated with
paraffin. It was nearly transparent.  Examination of the reagents showed
that the 1st Clear-Rite station appeared to contain water mixed with the
Clear-Rite. I believe that the ETOH preceding the Clear-Rite may have been
95% rather than 100%.
I have tried reversing the processing back to the PBS buffer overnight,
then reprocessing as listed above.  When sections are cut, on microscopic
examination the tissue appears somewhat desiccated and the muscle has a
shiny, transparent appearance and the muscle fibers are not visible.  H&E
staining seems OK in some areas of the tissue, other areas (epidermis and
hair follicles) sometimes appear to have a haze over them.  The muscle
stains with eosin only.
Can anyone suggest what might be causing this problem?... and more
importantly how can I fix it?  I'll appreciate any suggestions.

Mary Ross
Research Associate
Mol Virol, Immunology, Med Genetics
Ohio State University