A nut, usually circular with serrated edges, is screwed down onto the minute
hand.
To remove the nut, hold the minute hand as close to the nut as you
can, and unscrew carefully. By holding the hand as near to the nut as possible
you minimize the risk of bending it.
Some later clocks are fitted with
slotted nuts for which the manufacturers had special tools. A pair of pliers
will normally slip off these nuts, damaging the finish. A simple tool that fits
most of these hand nuts is readily available. Hour hands should simply pull
off.
Repairing Your Own Clocks by Mervyn Passmore