The phrase "to clear the mind" means to empty your thoughts and have a peaceful, calm state of thinking with no distractions or worries. Full definition
This will help clear your mind from all of the older accomplishments and experiences and allow you to focus on the more current experiences you can remember. (exclusive-executive-resumes.com)
Before I continue describing the event, try clearing your mind for a minute and imagining the scene described by the artist statement. (burnaway.org)
Many people claim meditation to be easier or more clear minded when they are not eating meat. (vikasayoga.com)