In Baltimore, a painting by Clifford Stilke and an Andy Warhol of the Last Supper are being sold at auction. Mada: The issue there is not simply about selling, but whether it's being sold too cheaply. Christie wants museums to become bottomless repositories of works of art that are never put on display,. So selling does have to happen occasionally. It just has to be done. In the full knowledge that trustees are exercising their fiduciary duty towards the institution and the public that visits and pays for it.