If it is a saliva test, you just need to be clean 2-4 days before the test. Make sure you brush your teeth before the test and gargle with mouthwash, preferably listerine. Like I said 3 days on average you will be fine for the saliva test. Hair tests are the worse, as thc can be detected for more than 90 days, and urine test for thc can be detected for 30-60+ days for a chronic user. Saliva and blood tests are detected for just 3 days on average for a chronic user. Good Luck