Atomic oxygen treatment has been investigated as an unconventional option for art restoration where conventional methods have not proved entirely effective. Exposing surfaces to atomic oxygen was first performed to investigate the durability of materials in the low Earth orbit environment of space. The use of the ground based environmental simulation chambers, developed for atomic oxygen exposure testing, was investigated in collaboration with conservators at a variety of institutions as a method to clean the surfaces of works of art. The atomic oxygen treatment technique has been used to evaluate ways to remove soot and char from the surface of oil paint (both varnished and unvarnished), watercolours, acrylic paint, and fabric as well as the removal of graffiti and other marks from surfaces too porous for conventional solvent removal techniques. This paper discusses the treatment of these different surfaces and the treatment results. -- ICCROM