1. Blackening Lashes With Dung
Um yes, you read that correctly. Ancient Egyptians would mix crocodile dung, water, and honey together to create one of the first mascaras in history. The dung would act as a colorant, while the honey would make it stick to lashes. While the mixture wouldn't necessarily kill you, you can imagine there was a case or two of pink eye. 

Image found on Pinterest here.