When my children were young and in school, we often had to treat them for lice until a co-worker of my husband told me about his experience. He had worked for years in a public school where head lice was endemic for reasons he couldn’t fathom. But he did figure something out. If you use a hair dryer every morning and night for 10 days, you will eliminate the lice. The heat destroys the eggs; the adults only live for 10 days. You can do it dry [baking them], wet [boiling], or oiled [frying]. We found that it always worked.
It’s a good thing to do as the lice medication is a nervous system toxin–putting the stuff on our children’s developing brains doesn’t make sense to me.