Yes, the sentence "I have so many drafts to clear" is grammatically correct.
It means that the speaker has numerous drafts (which could refer to written documents, emails, or other forms of preliminary work) that they need to go through and either finalize, delete, or address in some way.
Here are a few ways to rephrase it:
1. "I have a lot of drafts to go through."
2. "I need to clear out all these drafts."
3. "There are many drafts I need