Trisha:

     I routinely embed retrieved orthopedic implants with adherent bone in 
Spurr's resin, as well as (occasionally) in PMMA.  I use aluminum foil baking 
pans.  I pre-polymerize a 1/2" layer of plastic in the pan before embedding 
my specimen.  When the block has ploymerized completely, I use a pair of 
needle-nose pliers to "rip/tear" a corner of the pan, and then peel the 
aluminum off of the block.  Sometimes, it's necessary to grab the foil with 
the pliers and, holding the foil firmly, roll the aluminum in the pliers, 
similar to the old fashioned key used to open a can of sardines (I'm really 
dating myself now!!!)  Use caution because the foil is sharp and can cause 
nicks and cuts on the fingers. (Ouch!!)  If the specimen is small enough, ie 
an iliac crest core biopsy, I use PMMA and embed in a glass scintillation 
vial.  When the block is polymerized, I place the vial into a plastic bag and 
CAREFULLY whack it with a mallet to shatter the glass, and then CAREFULLY 
retrieve the specimen and rinse in running water to remove and glass 
fragments.

Hope this helps!!
Feel free to give me a call if I can help you!

Regards,
Diane Mahovlic, MLT/HT(ASCP)
Orthopedic Pathology Laboratory
The Cleveland Clinic Foundation
9500 Euclid Avenue
Cleveland, Ohio   44195
216-444-0166