clear one's head
clear one's mind

He thought about trying to clear his head and decided against it.

He needed a long, hard run to clear his head.

Perhaps a few hours away from it would clear his head.

Maybe he should get away for a while, give himself a chance to clear his head.

She wanted to try to clear her head to be able to think.

"He needs time to clear his head from that big right."

He was suddenly trying to clear his head, and have a better look at the guy, but what had the man just said?

One thing was certain, being around him wasn't doing much to clear her head.

There was only one sure way to clear his head.

For a moment she tried to clear her head and think about what was going on.