Lots of effort. There is a large movement to not coat the head with Permethrin or lindane due to potential neurotoxicity, and the risk is relevant. Non medicated products like licemd or ovid are effective, but nothing works better than the nit-loosening gel (ok, so it's not totally natural), the fine toothed comb, and lots of time and effort getting out all nits and lice. Then repeating the effort.
Tx of lice. Requires accurate identification of nits ; / or lice. Natural remedies for lice include application of olive oil, mineral oil or mayonnaise to the head/ hair. These oil-based products smother the louse. Work carefully through hair ; remove individual nits. Purchase a special lice nit comb to aid you. Check for nits ; remove as seen over the next 7 to 10 days. Wash clothing or linens in hot water.