Frequently works on paper and documents become stained either by an accident, or by mold. When these stains interfere with the aesthetic appreciation of the artwork or document, stain reduction treatment may be an option as a method of rehabilitation.

Stain reduction is a highly aggressive, invasive and non-reversible treatment and must only be used as a last resort when there are no other viable options. Essentially stain reduction is a bleaching process achieved either by the use of chemicals, or by exposing the art object to strong light while submersed in a liquid.

Understandably only works that are deemed stable and un effected by the chemicals would be candidates for stain reduction treatment. All components of the artifact need to be carefully considered and tested for solubility and fading. This includes the medium of the work, inks, paints, signatures, the fibers and the sizing of the paper support, chemical brighteners in the paper if any, and many others. Even after careful testing, long exposures to powerful chemicals may produce unpredictable results and result in undesirable changes in the design media and weakening of the support.

Successful stain reduction however, often results in dramatic improvement in appearance and is responsible for rehabilitating many works which would otherwise would be relegated to storage.