You can delete clocks if you no longer need them.
Choose View > Clocks.
Select one or more clocks in the list.
To select clocks that are next to each other (contiguous) in the list, press the Shift key and then click the first and last clock; to select clocks that are not next to each other in the list, press the Command key and then click each clock.
Click the Remove (-) button at the bottom of the list or press the Delete key.