Clean the lithograph by gently rolling crumbs of white vinyl eraser over it. The crumbs will pick up any dust and dirt from the surface of the lithograph without removing ink or damaging the paper. Work in one section at a time to remove spots or stains carefully. Brush the crumbs off the lithograph with a dry, soft-haired brush after removing dirt.
Remove any backing attached to the lithograph by gently peeling the lithograph away from the backing, using a sharp craft knife to scrape the backing away where necessary. This process may take several days depending on the amount of backing attached to the lithograph. If the lithograph is heavily glued to its backing and does not come up easily, take it to a professional restorer for removal. If there is no backing, you can skip directly to matting and framing the artwork.
Soak the lithograph in cool, clean water to remove any last vestiges of backing. When the lithograph is submerged, use the craft knife to gently scrape away the remaining backing. Allow the artwork to dry completely, using a drying rack or weights to hold down the corners, so it dries flat.
Mat the lithograph with museum-quality archival mat stock and frame it using museum-quality UV-protective framing glass. Hang the lithograph out of the sun or direct light.