Hi,
Okay, I hope you're ready: the simplest, quickest, chemical free way to rid your household of lice is A STRAIGHTENER.
Seriously. A high-heat (200 degree) hair straightening iron kills lice, nits and eggs in one fell swoop. A local girl (I'm overseas right now) won the science fair testing the theory and after extensive media coverage it was put to the test by adults.
So I tried it. One treatment, 100% success. You can go directly to the straightener or you can follow my routine, either way will work. If you opt for just the straightener, just go sit your kids in the bathroom and go for it. Otherwise, here's what I do:
1) Put child in bath and cover head with conditioner -- I use Pantene, nothing fancy. THE CONDITIONER PARALYZES THE LICE for about 20 minutes. If your child dunks his head they will literally float out of the hair. Then use a nit comb and run through the hair to get the rest of them out -- the conditioner makes this easy and painless.
(I do this because, frankly, it really grosses me out to think of ironing the adult lice AND lice have a tendency to kind of free-fall to freedom in a crisis. Better to throw the more agile critters out with the bath water.)
2) Dry hair COMPLETELY. No dampness. (dampness + straightener = steam= pain)
3) Take small sections of hair and slowly run the straightening iron across them -- just like you would on your own hair. Any remaining lice, nits and all the eggs are killed completely.
4) Nit comb in bath with conditioner every 3 days (hatching cycle) for about 9 days just to double check. I've never had a single nit hatch, much less a full recurrence -- and considering that we've got a lovely 'poison resistant' variety of lice in this country, that's saying a lot.
I hate using the poisons, so even before I learned the straightening trick, I avoided chemicals. I simply did the conditioner/comb routine religiously *every day* until they'd all hatched and been killed. It takes more attention to detail and I remained paranoid about a week longer than I would have with poison, but IT WORKED and I didn't have to use the chemicals.
Best of luck and remember -- this is NOT a hygiene issue, in fact, it's a testament to your kids' nice, clean, appetizing scalps. Now go fry those little suckers! lol :-)