The Minnesota Department of Health lists the recipe for a vinegar nit treatment as one to one of water and vinegar. This means that if using 1 cup of water, add 1 cup of vinegar for the appropriate recipe for nit removal.
While state health departments recommend using over-the-counter lice products, there are people who claim that alternative treatments are effective. Vinegar treatment is meant to help loosen nits after the live lice are dead.
To use vinegar, simply soak the hair in the mixture for at least 30 minutes for up to 1 hour. After the designated time, use a lice comb to remove the nits and then rinse the vinegar from the hair.