Kari,

It seems the hazy staining could be from the deparaffination process.
Instead of 6 minutes in one bucket, we do 2 minutes each in 4 buckets of
Xylene.  We do not use an oven or microwave in this process.  As someone
else pointed out, the problem may also be the Xylene itself has water or too
much ETOH run-over in it.  The holes in your blocks may be an infiltration
problem in the processing program.  We soak our embedding pans in Xylene,
and have never had a problem with cleanliness.  When embedding, we fill the
bottom of the embedding pan with paraffin, put it on the hot plate for about
5 seconds (the paraffin in the pan should now be fully liquefied) take the
tissue and place it in the bottom of the pan, put a cassette top on the pan,
fill top with paraffin.  Hopefully these suggestions may help.

Tom Galati
Lab Manager
Histo-Scientific Research Lab.
(540)856-2222