I have a skull that has the very top layer of skull flaking off. I used beetles, then degreased at 118F with dawn and a cup of ammonia in 5 gallons of water. I whitened by soaking in BO to get the nasal bones and teeth white for three days, then whitened the top of the skull with BO and Basic White. It needed two treatments. I did a second at the same time in the same bucket with the same whitening procedure and it is not flaking at all. This is the first time this has happened with any skull I have done. Any ideas on what may have happened? How do I take care of the flaking skull. There are loose flakes only on the top where I put the BO and Basic White mixture. The BO soak did not touch the top of the skull where it is flaking. One more thing. The same Basic White and BO mixture was used on both. I did the skulls at the same time and mixed up enough for both.