Be careful with Vinegar. I put it on DD's hair for nits once and she broke out in hives.

Any conditioner will do. Last time my girls had them I used a product called Lice Breaker. It is like conditioner, goes on dry hair then you comb it through before washing it. It was really good, killed all the nits, amde their hair nice and shiny and DOESN'T smell! I bought the matching comb which was fantastic too. It got all the eggs out easily.