Soften the glazing on a section of windowpane with a heat gun and remove it with a putty knife. Repeat this process for each section of glass.
Pry out the old glazing points with the putty knife or a flat tipped screwdriver.
Remove each section of glass and clean out any debris in the frame with a wire brush.
Measure the dimensions of each opening in the window frame. Subtract 1/8 inch from each of these dimensions to leave room for glazing.
Cut sections of mirror and cardboard equal to these dimensions, using a glass cutter for the mirror and a craft knife for the cardboard. You will need a section of mirror and cardboard for each opening in the frame.
Back each section of mirror with a piece of cardboard and place it into a window frame opening. If a mirror doesn’t fit, go over the problem edge with grozing pliers.
Drive glazing points into the window frame every 4 inches, using a putty knife. The glazing points will hold the mirrors in place.
Screw two swivel hangers into the back of the window frame, 1/3 to ½ of the way down from the top.