When you get the upper hand on someone or something. Can also be information that is so juicy that you cannot wait to tell your homies.
What you use when a person threatens you with some form of punishment.
The threat of embarassing someone because of pure dirt can be enough to conduct blackmail effectively, provided the threat is believable.
"Jessica stands no chance. We have pure dirt on her. "
"Bro, are you home? I need to come over. I just found out some pure dirt."