A lithograph is a reproduction of an original painting. Just like the originals, lithographs need to be cleaned when they accumulate dirt. Some forms of dirt are best removed by professionals, but cleaning smoke, yellowing and oil spots from a lithograph can be done at home by using household items.
Lay slices of bread onto a drying rack. Let the bread sit overnight. The bread will dry and lose moisture. The less moisture in bread, the more absorbent it becomes.
Put the dried bread into a food processor.
Process the bread until it forms coarse breadcrumbs.
Lay the lithograph on a flat surface, such as a table or countertop, so the smoke-damaged area faces upward.
Spread an even layer of breadcrumbs over the smoke damage. Do not press the breadcrumbs into the lithograph, or you may damage it. Let the breadcrumbs sit, undisturbed, for at least one hour.
Brush away the breadcrumbs with a soft-bristled brush.
Put on a pair of chemical-grade rubber gloves and a ventilation mask. Work in a well-ventilated area.
Add equal parts water and hydrogen peroxide to a plastic container large enough to hold the unfolded lithograph. Add enough water and hydrogen peroxide to fill the container with at least half an inch of solution. Add two to three drop of ammonia to the solution.
Dip the lithograph into the solution and gently move it around until the yellowing of the print begins to fade. Depending on the severity of the yellowing, this process may take a few minutes.
Rinse the lithograph thoroughly under cold running water.
Repeat if necessary.
Lay the lithograph on a drying rack and allow it to air-dry.
Place the lithograph between two sheets of paper.
Soak the bristles of a soft-bristled brush with rubbing alcohol.
Massage the oil spot with the bristles gently until the oil begins to release from the lithograph. The sheets of paper absorb excess moisture and prevent it from damaging the lithograph.
Dry the lithograph by patting it with a clean towel.