Natalie,
After staining with aqueous fixative, I always rinse with dh20 and
air dry GMA sections.  If you are using a alcoholic stain, such as
alcholic eosin you may need to dehydrate thru alcohols and clear in
xylene to coverslipp, but do it quickly and gently using isopropal
alcohol (not ethyl), because this tends to make the section float
off.  The clumps you describe in your PAS stain may be the result of
the GMA lifting up and stain being traped under the plastic.
Patsy Ruegg