Use a flat screwdriver to lift the prongs on the back of the hanging window. Remove the back and the glass. Set aside the back for another project. Use a paper towel moistened with rubbing alcohol to clean the glass. Apply extra sticky tape on the edges of the back of the window frame. Place the glass centered on the window so it is secured by the tape. Bend the metal prongs back over the edge of the wood frame. Turn the piece over.