When my daughter was at juinor school and got them a couple of times, a hairdresser suggested that when i washed her hair i added salt the the water i used to rinse it,she claimed this dehydrated and killed them. I followed her advice and she stayed clear from then on, of course there is nothing to say this was why, it could of been coincidence, but as it was non toxic i was happy do continue doing so lond term, and then her doing it herself until she left school.Good luck, nit`s are the curse of the school years xx