polish up vs brush up

polish up and brush up both are verbs.

Word	Noun	Adjective	Verb	Adverb
polish up	No	No	Yes	No
brush up	No	No	Yes	No

As verbs, polish up and brush up are synonyms defined as:

polish up and brush up: bring to a highly developed, finished, or refined state

Other synonyms of polish up include polish, round, round off.

polish up (verb)	brush up (verb)
bring to a highly developed, finished, or refined state	bring to a highly developed, finished, or refined state
	refresh one's memory