Get crabs and plant a couple of them on your head. As everybody knows, lice are democratic and crabs are communists. As the crabs start to spread and take over more and more hairy territory, tensions between the crabs and the lice will grow. The crabs you dropped on your head will really help to strain relations. Now, you have to instigate wars between the two. After enough time, they will develop nuclear weapons. You have to launch the first nuke, otherwise the threat of mutually assured destruction will keep the two from eradicating each other. Then, watch the warheads fly, and before you know it you're free of lice, crabs, and hair.