How do you clean 1964 quarter?

To clean a 1964 quarter, use a gentle method to avoid damaging the coin's surface. Soak it in a solution of warm water and mild dish soap for about 10-15 minutes, then gently scrub with a soft toothbrush or cloth. Rinse thoroughly with clean water and pat dry. It's important to note that cleaning coins can reduce their numismatic value, so consider leaving valuable coins uncleaned if you're a collector.