This ultimately means many of the skulls that we see today that have some trephined have been robbed of their precious metals. What a sophisticated society to not only have the resources, the economy and the skill to this but it would seem that there is something said about the value of life. The golden plating is a testimony to the ancient Peruvian’s technology and their respect for life.
Technology as in this case like many others have to do with precious metals and chemicals that are easily removed by invaders, lost in fires or diluted by the elements.
~Chris L Lesley