The antonyms for the phrase "polishes up" can be numerous, depending on the context of usage. Some possible antonyms can be tarnishes, dulls, roughens, grimes, stains, or scratches. Tarnishing can occur on various metal surfaces like silver or brass, when exposed to air or humidity for a long time. Dulling can happen to a glossy surface, reducing its shine or luster. Roughening a surface can increase friction and make it less smooth. Grime and stains can be unhygienic and can detract from the appearance of a surface. Scratching can damage and mar the surface, making it look worn-out. Hence, using the correct antonyms can provide a clear picture of the quality of a surface or object.