After softening up the nits with the treatment of your choice, use a nit comb. A nit comb is a sturdy, short in length comb with very fine spacing between the teeth, typically supplied with the treatment of your choice when you buy an over-the-counter treatment.
There is a product called Lice Free. It comes in a spray bottle. They sell it at walgreens and cvs. It is all natural and by far without a doubt works the very best on killing the lice and pretty sure eggs. Then have child sit down and comb and comb there head and rinse the nits and bugs out in a large pan of hot water. Use best metal comb you can buy. Trust me. I have two girls with long hair and this stuff was amazing. The easiest to use, the safest, and cheapest (around $10). I put it on top of my list right next to buedroux butt paste. whatever you can't possibly wash like pillows, blankets,and stuffed animals you can put it in the dryer on very hot for about 30 min or more atleast until you can get to it because sheets and pillow cases come first. you can also bag those type of things for like a month and they will die.