Another one of my maceration projects was this deer skull. It was given to me by a hunter friend of ours after it had been buried for several months. That process rotted the outer skin and muscles off, but the brain was still a dried lump inside! After months of maceration outside in a bucket of water, I finally got it fairly clean.
When all the tissues where gone, I soaked it in a solution of hydrogen peroxide and a little water. I could only find bottles of 3% solution but that seems to have worked well. I bought 7 bottles and poured in enough to completely cover the skull.
I added a small amount of water in case of evaporation. I left it alone for a week and here is the final result.