Bought this critter online. Seems to be an older boar. Initially, I expected a raw, frozen head to work on but the seller decided to rot stuff off and ended up burying it. This now has been soaking for over a week in heated Dawn and water. Some grease is gone but the brown stains are remaining. Not sure what type of dirt it was buried in. Headed off to the store now to invest in a few gallons of ammonia to try that for another week or so before I soak it in peroxide. I suppose I can live with the color if I can't get it out but the grease has got to go.