Each panel is examined carefully with a documentation in description, photos and templates. If the lead is not corroded, it is preserved. Otherwise, decomposed lead is removed and the panel is releaded and puttied. Broken panes of glass are replaced with glass that most closely matches. If a pane is cracked very slightly, the pane is preserved with a very fine line of copper foil and solder, unless the line is going to be detrimental to the design. The process of restoration is more detailed and labor-intensive than creating a new panel.