Will you be clean after 4 days for a drug test?

No. Most drugs can be detected in your system for as long as thirty days, longer for some people. There is no effective means of erradicating traces in the test sample. the only means of providing a clean sample is to not do the drugs. Your best bet is to come clean with your probation or parole officer, and hope he offers you rehab instead of violating you. You might even ask for rehab as you notify him.