Removing window sashes for cleaning or repairing the window frame is different among the many manufacturers. Removing an Anderson window sash requires removing the lower jamb liner. The jamb liner is a plastic liner covering the lower portion of the window tracks on the left side of the window frame. Removing the liner enables one side of the lower and upper sash to swing freely away from the window frame.
Look for a sill stop in front of the lower window sash. The sill stop is a small piece of trim that runs the width of the window and sits on top of the windowsill. Remove the screws securing the sill stop to the window sill with a Phillips-head screwdriver, if your Anderson window uses a sill stop.
Locate the two screws securing the lower left jamb liner above the left side of the lower window sash. Remove the screws with a Phillips-head screwdriver. Raise the lower sash to the fully open position. Remove the screws on the bottom of the left jamb liner with the Phillips-head screwdriver. Place one hand on the top half of the lower jamb liner, and pull the bottom of the lower jamb liner away from the window frame. Remove the lower jamb liner completely away from the window frame.
Close the lower sash, and pull the left side of the sash away from the window frame. Grasp the left sash cord with one hand and pull down to provide slack at the sash. Unhook the sash cord from the left side of the sash, and slowly release the sash cord.
Pull the right side of the lower sash away from the window frame. Pull down on the right side sash cord to provide slack in the cord by the right side of the window sash. Unhook the sash cord from the lower sash, and slowly release the cord. Pull the lower sash completely out of the window.
Pull the upper sash all the way down to the window sill. Remove the upper sash in the same manner as the lower window sash.