To access the steam pin:
Insert a Phillips head screwdriver into the end of the Steam Knob and unscrew the screw completely.
Slide off the  Steam Knob.
You may be able to unscrew the Steam Valve Collar without removing the Steam Collar Insulator first. Attempt to unscrew them both together by hand. If that does not work, then go to steps 4 and 5.
Remove the Steam Collar Insulator. This can be done by hand.
Unscrew the Steam Valve Collar using your hand by turning it counterclockwise. If your machine is old and has not been cleaned recently, you may need to use some pliers. Do not use pliers directly on the  Steam Valve Collar, as it will scratch the surface.
Unscrew the Steam Pin using your hand by turning it counterclockwise.  If your machine is old and has not been cleaned recently, you may need a small spanner.
To re-assemble, repeat the process in reverse.