The antonym for "polished up" could be "unclean" or "grubby". "Polished up" implies that something has been made clean or shiny, whereas "unclean" or "grubby" suggests the opposite. Other antonyms for "polished up" could include "shabby", "raw", or "rough". These words describe something that is unrefined, unfinished, or in a state of disrepair. Alternatively, the antonym for "polished up" could be "neglected" or "ignored". These words suggest that something has been allowed to deteriorate, rather than being cared for and maintained. In any case, the antonyms of "polished up" describe the opposite of something that has been made to appear or work better.