I have never had an old skull or "rotting" skill stink from boiling. just put some Dawn in it and some oxyclean from the get go and it will cover or take care of the smell. Pop the ear bones out and it will make is quick and easy to get the brains out.
With a power washer and boiling you should be able to have it cleaned up in 1-1.5hrs or less.
With a power washer and boiling you should be able to have it cleaned up in 1-1.5hrs or less.