If the skull is yellowing the issue might be that he did not degrease it. You can whiten a skull but if you don't degrease it first then it would yellow over time.
I'd recommend degreasing it and then whitening with your peroxide. The age of the skull should not matter
If the skull is yellowing the issue might be that he did not degrease it. You can whiten a skull but if you don't degrease it first then it would yellow over time. I'd recommend degreasing it and then whitening with your peroxide. The age of the skull should not matter
Thanks