[Histonet] cell block fixation

[Hutton, Allison]

We recently switched vendors for our formalin and while we have not experienced any difference with our surgical specimens, our cell blocks from body fluids have been giving us a great deal of trouble.  The button that we get never seems to harden, leaving it sort of gelatinous, even if left to sit in formalin for days.  We are able to get sections off of these cell blocks, however, the slides are blank by the end of the staining process.  This is only a recent development that seems to coincide with the time we switched formalin vendors and it only happens with body fluid specimens (FNA specimens don't seem to give us as much trouble).  The composition of the formalin is almost identical between vendors.
Can anyone help me explain why this might be happening?
Thank you in advance,
Allison