Once a WeekDust. Nothing dulls a mirror's sheen like a layer of dust. Use a microfiber towel or another soft cloth that won't scratch the finish or leave lint flecks. Polish. Remove smudges, fingerprints and other marks with a soft cloth and a mirror-safe glass cleaner (check the label). Spray cleaner onto the cloth rather than onto the mirror. A solution of distilled white vinegar and water can help wipe away stubborn smears. Be sure not to leave residual streaks as you go.Once a MonthInspect for chips and scratches. Mirrored finishes are prone to dings, so give your piece a regular once-over. If you spot a flaw, you can have it professionally repaired. Also, check for sharp or jagged objects that can scrape or nick the finish if they happen to fall on it or get dragged over it.