Have a very special buck I'm working on that was found dead and I macerated to take off the little bit of meat that was left. I then degreased for a couple weeks. This skull was found in oak country and on half the skull and part of rack what I believe are tannin stains are being impossible it seems. I soaked over night in BO, let dry, and the orange/rust color was still horrible... I thought possibly iron out would move the stains but after 40 minutes not any difference at all... I just put back in BO for another night but I'm afraid its not going to do much... Any other suggestions? Have some of you pros ever had a skull that just would not whiten?