Quoting ducky:“ But will suffocating the lice kill the eggs as well?”
I think so. I used to get lice so bad that it would never go away. After the vaseline I never had any problems. The reason you leave it in for 3 days is because it takes 2 days for the eggs to hatch if I remember right. They won't be able to lay new eggs on the hair shaft because it'll be too slick, and the old eggs will be suffocated too. Something like that. XD