Lisa
Besides tea tree oil, I've heard of adding any of the following; rosemary oil, lavender oil, eucalyptus oil, and peppermint oil. I know peppermint is a deterrent for cupboard moths so there might be some help in that, also it might ease the smell of the tea tree oil (yuck). These should be used in only teaspoon-or-less sized applications, mix into a base oil of olive or mineral oil probably in the hand with normal shampoo. Don't know for sure if it works but I'm about to try it because I just got head lice from my neice and have read just about everything on the Internet!!! Also, someone said if you take garlic capsules the lice don't like you much anymore!! I will try that too. Garlic is also good for your overall health. Can't hurt. If anyone reads this let me know how you do.