Chiming clocks often feature Westminster chimes and other melodies. Some clocks triple-chime and many chime every 15 minutes. Once the novelty has worn off, you may decide that you'd like to silence your clock. Many classic clocks have two ways to shut off the chime. One method shuts the chimes off altogether, and one method just shuts them off at night.
Allow the clock to complete its sequence of chimes and then allow the clock to exit the chime phase, which safely will be half-way between chime sequences. So, if the clock chimes at the top of the hour and again at 15 minutes past, make the settings change at 7 minutes past to be safe.
Determine if you'd like to shut the chimes down altogether, or just at night. Take a look at the clock controls. Look for a lever or setting called "Chime Silent" or similar. The setting may be on the clock face and not near other controls. If you'd like to shut down the Westminster or other chimes, select the "Silent" option.
Look for a lever called "ANSO," which stands for "automatic night shut-off," if you just want to stop the clock chiming at night. Often this setting will stop the clock chiming from 10:00 p.m. until the morning. On a Bulova, where it's on the right side of the face, the lever will stop the chimes until 6:00 a.m. or 7:00 a.m.