My DD had lice a couple times and shared them with me once

.
The first time she had lice we did the Rid treatment and the lice laughed at us. OK ... maybe not laughed but it didn't slow them down much. After 2-3 RID treatments and literal nit picking for nearly 2 months we STILL had lice I knew I had to try something else.
I *swear* by this method called "The Lice Program":
http://www.microscopy-uk.org.uk/theliceprogram/index.html
It works great if your school does not have a "no nit" policy because it doesn't bother with nits. It removes
live lice when they are big enough to remove. First the egg layers and then the juveniles as they hatch and grow. I admit that I was originally grossed out by this program because (1) at 21-days it took too long and (2) it left lice (nymphs) in the hair and I wanted those lice out NOW. But ... after my failure at more traditional methods I had nothing to lose in trying it.
After 21 days the lice were gone. I was mad that I wasted 2 months trying to poison them and dousing them in olive oil to no avail. When my DD came home a second time with lice, I went right to this program and they were gone in 3 weeks and she never missed a day of school.
There are two things that I really like about the program. The first is that I don't have to expose my family to chemicals and toxic poisons. The second is that there are rest days built into the program to allow the lice to grow big enough to comb out. Combing for lice is mentally draining on both the parent and the child when there seems to be no end in sight and I found the breaks to be a blessing.
I also have tips on combing ... first off I used one of the narrow teeth combs available at Walgreens with the little magnifier in it. That way I could make sure I was getting a little bugger and not something else. I also would have my DD wash her hair and leave conditioner in it for combing. The lice can't move easily through wet hair and the conditioner made it easy for me to comb. When combing was done she would rinse the conditioner out. ETA: I would section off her hair with metal hair clips (the kind that stylists use) and then everything went into a daily bath of water with a tablespoon of bleach in it.
FWIW, if you are picking nits any "nits" more than an inch from the scalp as really empty egg sacks and you're wasting time and energy unless your school has a no-nit policy.