Frozens can be done on any NBF fixed tissues, you can soak them in 10% -
15% sucrose overnight or blot them a tidge after rinsing with water, then
freeze.   Sucrose cryoprotects and can give less crunchy icy sections, good
morphology

Use plus charge slides, air dry for 30 min to 1 hour, no further post fix
needed.  I then do Churukians Oil Red O, it eliminates gooey propylene
glycol, he published this in J of Histotechnology last year, wonderful and
easy.

After staining, a gentle water rinse, counterstain with hematoxylin, blue
and mount in aqueous mounting media.  

This has worked on trout livers and bovine skin samples (not the nicest
tissues to cut fixed/frozen!).

Good luck
Gayle Callis
Veterinary Molecular Biology
Montana State University
Bozeman MT 59717-3610
406 994-4705
406 994-4303