I had a macerated white tail deer skull in a mixture of clear detergent (Palmolive) and 120F water for a total of 5 weeks. Multiple water changes when sufficiently murky . The fourth and fifth week had the same solution because it had stayed almost perfectly clear the whole time. Took it out, rinsed it off, let it dry for 10 days. Saw a small spot of obvious grease (looked translucent) on the top of those two long nose bones. In addition, directly above where the brain would be that whole top was stained a dark yellow, as well as other parts of the skull looked good but still had varying shades of yellow areas. I decided to put back in the degreaser, and for the first time try using ammonia. I ran about 5 cups of 10% ammonium hydroxide (Ace ammonia) in 5 gallons of water, heated to 120F with about a tsp of detergent. Within a day and a half the water turned a straw yellow and over the next 4 days there were numerous 1/4" round globs of floating fat. About mid way through I had added more ammonia because at 120F you could tell by the smell a lot of the ammonia gas had flashed off. Even with the water surface covered, a vent hood is needed. The bottom line is, I couldn't believe there was still this much fat still in the skull, and it appears the ammonia has done way more in 3 days or so than the detergent did in 3 weeks! I changed the ammonia water, rinsed. Now i have it in about 8% ammonia hydroxide, sitting for a few days at room temp. After a few days i will either heat this, or dilute it down like i did the last round @120F. Not sure if some of the results were due to the drying period. Do any of you only use ammonia and water heated to degrease? I couldn't see a difference in color of the still wet skull but i'm telling you i removed about a 1/2 tsp total of floating fat globs within 3 or 4 days of the heated ammonia/water mix. Who knows how much dissolved. The water was in a white 5 gallon bucket, with a good light i couldn't see down more than 8" when it was changed. I'll update this as it progresses. So far Im impressed with the heated ammonia solution.