Here is the story with this skull. Its from aprox 4.5 y/o whitetail buck. Was boiled by a "skull guy" (not sure if brain was left in or not). Never peroxided. After it was boiled I took possession of it and it was degreased in dawn/water/120-125F for aprox 12 weeks. The last several weeks nothing came out of the skull. Skull dried, still had grease, was still learning at the time and figured that was about as good as it would get. Let it be a couple years, then started experimenting with ammonia in 120F water on another skull and loved the results. So I took this problem skull which has sat 2 years since last degreasing, and put it in the 120F water and ammonia mix and within a day there was massive "pepperoni pizza" colored type grease coming out of this thing! So it def hit the grease better and removed a lot for several weeks. I forgot exactly how long I did the ammonia/hot water thing but I did it until there was nothing else coming out. Let it dry, grease was vastly better than before but still has a good amount of grease on the forehead. Sat another year or two since then, and I decided to put this #%#% into acetone which I have never used before. Its been fully submerged outside (summer temps 70-90F) for a couple weeks now. I'm going to let it sit a month (too long or short?) and take it out. Here is the question, when I take it out should I let all the acetone evaporate out and see what it looks like first, or should I take it while still wet with acetone and slam it right into detergent and hot water degreasing mix, or hot water and ammonia mix like I've had good luck with using? I'm doubtful that the acetone will remove everything that is left by itself without hitting the skull with a post-acetone degreasing process. I've had so much trouble with this skull I'm fearful that allowing the acetone to just evaporate off before going further, is going to have grease redistributed in the skull and then get "locked down" again making it more difficult to remove with next method. What has your experience been with this?