Garlic and lime juice. The smelly compounds found in garlic can suffocate lice, and the acidity of lime juice can break down their soft bodies. Thoroughly mash up 10 cloves of garlic until most pieces are smaller than a pinhead. Then add enough lime juice to make a thin gravy-like concoction. Apply to the scalp first, then squeeze outward to the ends of the hair. Allow this to sit for about 30 minutes, then wash it out. Repeat this treatment a few days later for best results.