I decided to repost this here, maybe make a sticky, so if/when someone needs it, it'll be in plain sight.
First off, let me say that I know for a fact that this works...I have school age children, and before we moved to B town, we lived in a town with a shitty school system, and my oldest daughter used to get them all the f'king time and bring them home to us.
Too many dreadie folks panic and end up shaving their heads because they believe that is their only option. Don't do that, please, dear Gawd. Also, avoid any kind of lice shampoo, prescription or over the counter. We found out that lice shampoos are like antibiotics....improper usage has lead to many bugs developing a resistance to the poison, meaning they won't die. Not only that, but generally the nits (eggs) won't die anyway because they are protected inside of their shell. Plus, those shampoos don't rinse very well, and you don't want nasty pesticides building up inside of your locks.
This is cheap, effective, and does not require you to chop off all your lovely locks!
To start, pull your dreads up and try to bun them up if you can, or at least pull it into a high ponytail. Use about a half bottle of rubbing alcohol (70% or higher) or however much it takes to cover your scalp. Don't worry about soaking your dreads, because the fumes will kill them (the lice) as much as the alcohol itself. Tie a plastic bag or wear a shower cap tightly around your head for about 30 minutes. It'll itch and its annoying and stinky, but it'll kill the bugs. Rinse it out, and watch the bugs fall out.
Now, you'll have to do this again in about 3-5 days because the alcohol only kills the bugs, not their eggs (remember, most of the actual lice shampoos don't kill the eggs either...) so you'll have to do this process over again to kill any newly hatched critters, before they have time to reproduce. At this point you really should be lice free, though I would suggest you do it yet again in another 3 days....just to be on the safe side.
This is a cheap, easy and very effective way to get rid of lice. It has never once failed us. Just make sure you do it in a well ventilated area (we don't need you passing out on alcohol fumes), and it helps to have a friend or relative to help so you don't accidentally pour the shit in your eyes. That shit ain't cool. Also, no smoking, as alcohol is highly flammable. (don't want you head to go up in flames, do you?) And ta-da! Lice free, for under 5 bucks, and without having you sacrifice your lovely locks! The alcohol rinses out with no residue, and it'll disinfect any wounds you have on your scalp due to scratching. It will dry out your locks if you have to do it very often, but not anymore so than any of those harsh shampoos would....this is nothing a little aloe wouldn't cure.
one more note...using tea tree oil in your hair acts as a lice/insect repellent. Dr. Bronner's makes a soap with tea tree oil, and that's what we use. You can also buy it as a fancy, overpriced spritzer to spray in your hair. I think you're better off with the soap, personally. We also use tea tree oil in the deep cleaning concoction. I've read that rosemary also acts as a lice repellent, though I've never used it myself.
The beautiful part about this treatment is that no matter how often you use it, it's guaranteed to work....Lice may develop resistances to poison, but they damn sure can't resist BREATHING! And that's what the alcohol does...it suffocates them. This will also work on undreaded hair, but you'll have a bit of a hard time with it because the dreadlocks tend to soak up the alcohol much better than straight hair will.
The only folks I would advise against this method would be folks with serious breathing problems, or young children...I mean, common sense tells us that young children+plastic bag on head=disaster. Plus, I'm not sure how safe it is to use full strength alcohol on little kids.
And....that's all! I hope this info might eventually be helpful to someone!