It seems it wasn't just the Celts who were given to post-mortem whittling of their fallen citizens' brain-cases. And since the ancient Egyptians' hieroglyphics were also their language, these skulls are in fact messages from the past.
We hired an Egyptologist to research the markings on this cheery fellow, which yielded the following:
2 pints of semi-skimmed
168 litres of asses' milk (need a bath)