Hi and thanks for you question.
Meth can be detected in a urine sample for up to 3-5 days after a single use. Chronic users, more sedentary users will retain the meth for a longer time period. The best way to eliminate meth out of the urine is to drink a gallon of water and get lots of aerobic exercise. If you pee into a cup, then make sure you use the pee that is in the middle of the stream. Let me know if you have an additional questions.
how long before the sample will test clean and how long will that last
It takes up to 5 days after a single use for the sample to test clean. It will take longer for long time users and those that use high doses.
Maybe for a chronic user.