Can Niacin And Water Help In Cleansing The Body With THC And Toxins?

I am currently on probation and I have 6 days to cleanse myself of THC is it possible to cleanse myself of niacin and water a friend told me I can take niacin and a gallon of water 6 days in advance in order to cleanse my system is it possible for them old was too if you have any information you can give me an order to cleanse myself in a short. Of time he told me niacin and a gallon of water a day for 6 days can cleanse my body of THC and any harmful toxins