Laurie,

Your observation is why I don't like using them.  I believe reagent gets trapped in there, and with the filling and emptying of the solutions, air bubbles get trapped too.  I figured not only is there a possible issue with something drying out, but the amount of carryover per cassette in my processing solutions is unacceptable.

Teri Johnson
Managing Director Histology Facility
Stowers Institute for Medical Research
1000 E. 50th St.
Kansas City, Missouri  64110
tjj@stowers-institute.org