clear one's head
clear one's mind

I went for a walk this morning, to clear my mind.

I told him to try to clear his mind of every thought.

She decided to say no more to him and tried to clear her mind for sleep.

He took a deep breath, trying to clear his mind.

He is just trying to clear his mind and throw.

"It will probably be good for me to clear my mind."

He took a deep breath, and tried to clear his mind.

He felt the need of exercise to clear his mind.

"I have to clear my mind and figure out what to do."

I told him to clear his mind, let it be dark.