Shine up can be replaced with a variety of synonyms depending on the context. For instance, "polish up" and "buff up" are both excellent alternatives when referring to cleaning and shining up surfaces such as furniture, floors, and cars. When used in relation to personal grooming, "clean up" or "spruce up" are common synonyms that can be used interchangeably with "shine up." Another related synonym is "glow up," which refers to self-improvement and personal transformation. Regardless of the context, selecting the appropriate synonym will elevate your writing and make your language more precise and engaging.