Most of us have been here more than once: a critical specimen, often the only one of its kind, does not embed properly. Usually the problem is incompletely polymerized resin. After the panic subsides, a limited number of options are left, and if the specimen is irreplaceable, there are no options, other than trying to salvage it the best way you can. I've had this problem before with low viscosity resins, but the following suggestions should work for other resins as well.

First of all, realize that reprocessed specimens are rarely as good as they would be if things went fine the first time around.