On Wed, 26 Apr 2000, Kelly Pruitt wrote:

> What can I do to keep my base molds from sticking to my blocks?  We clean them in xylene and then soap and water.  We air dry them.  We treat/spray them while they are clean with Histo Prep after they have air dried.  I give them a good coating when I use the Histo Prep.  The larger molds are usually good for one use.  On the biopsy molds, they stick every time.  It doesn't matter what I do.  

Stand the mould-with-block on the floor of the freezing
compartment of a refrigerator and leave it there for about
a minute. The wax block will then pop out easily. I
suppose the contraction of the metal loosens its adhesion
to the wax. I use Tissue-Tek embedding rings, and find
that the freezer trick is needed for about 50% of all
blocks. It always works, whereas release-compound works
only sometimes.

 John A. Kiernan,
 Department of Anatomy & Cell Biology,
 The University of Western Ontario,
 LONDON,  Canada  N6A 5C1