Open the casement window with the window crank. If the handle is worn and only spins on the crank stem, pull the handle off the crank stem. Tighten the jaws on a pair of vise grips around the crank stem and open the window crank using the vise grips as the crank handle.
Open the window until the roller bushing on the end of the crank arm lines up with the notch on the window track. The bushing resembles a roller on the end of the arm that moves the casement window open.
Press the window frame slightly with one hand and maneuver the arm out of the window track. If your window crank has a pivot arm attaching to the bottom of the window frame, disconnect the pivot arm by removing the screw on the bottom of the frame with a Phillips-head screwdriver.
Find the screws that secure the decorative casement cover over the top of the window crank. Remove the screws with a Phillips-head screwdriver and lift the casement cover off the window crank and away from the window frame.
Remove the two screws that secure the window crank body to the window sill with a Phillips-head screwdriver. Lift the window crank off the sill and out of the way.