Clue
I'm sure it's somewhere in the guidelines. Basically, you're supposed to transcribe what you hear. Since readability is a priority in clean verbatim, you're only supposed to "fix" slang phrases and skip fillers, false starts, repeats, things that don't add any useful information to the conversation.
Just to make it clear, "wanna" becomes "want to", "gotta" becomes "got to" in clean verbatim. I don't know if cursing is allowed here so I'll play it safe, a swear word remains a swear word in clean verbatim. You don't "fix" it, you don't use "****", you don't use "[swearing]", "[dirty word]", or "[expletive]". Also, "I was, like, so sad" becomes "I was so sad". "The tree was kind of tall" becomes "The tree was tall". "We went, you know, I mean, you know, to the movies" becomes "We went to the movies", etc.
In the end, just stick to the guidelines and you'll do fine. Good luck.