The only hog I’ve ever done was a pain to degrease. I started by leaving the skull in dawn and water in a bucket to degrease and i would change out the water every few days. This drug on for 2 weeks or so and it wasn’t degreasing well. I ended up getting the 40% peroxide cream from Sally’s beauty supply and putting a 32 oz container of it in my boiler and then put the skull in and covered with water. I let it simmer for 30 or 45 minutes and it decreased the heck out of it and made it a beautiful white. It’s been that way for probably 2 years and has not greased up at all. Doing a hog skull is wayyyyyyyy different than a deer head in regards to degreasing.