We use a product from Surgipath called Decal I,  it contains Formalin,
Formic Acid, Methenol, DI water.  But we routinely do Irons stains on
bone marrow core biopsies.   We place the core biopsy in the decal for
approximately one to two hours.  It contains a fixative so it is safe to
place in decal immediately.  Hope this helps!  Donna