Answer: brushup

AnswerCrossword Clue
BRUSHUP

Renew a skill

BRUSHUP

Refresh one's memory, as in "... your Shakespeare"

BRUSHUP

Go over one's old notes

BRUSHUP
Review for a test
BRUSHUP
Refresh one's knowledge (with "on").
BRUSHUPRefresh one's memory of.
BRUSHUPTake a refresher course.
BRUSHUPRevive a skill, with "on"
BRUSHUPReview
BRUSHUPReview for finals