Designed by Henry Bacon, the Lincoln Memorial was built between 1914 and 1922, and dedicated in May of 1922.  The interior of the memorial is constructed of limestone and marble, which had developed a ring of collected dirt and oils on the walls and columns over its 90-year life span.  This ring was the result of physical contact by millions of visitors; it included the area from the floor to approximately 7 feet high which was contained within the bottom three courses of stone.

The contract consisted of documenting the stained wall surfaces and columns inside the memorial chamber, testing cleaning methodologies and providing treatment recommendations to the National Park Service, using the approved methodology to clean ring stain from the lower portion of the walls and columns of the entire memorial chamber, and providing a final treatment report.  Previously approved treatment recommendations consisted of a combination of solvent-based paint stripper with non-ionic detergent and steam.  Given that visitor access to the monument would remain open to visitors while work proceeded, WEI recommended an odorless, user-friendly latex poultice that would be less disruptive to the visitor experience.  The poultice was applied to the surface and left on for approximately 24 hours to cure and draw out the grime from the stone, after which it was removed by hand.  The material even drew out graffiti and deeply absorbed soiling that had previously been removed at the surface.  The stone was wiped with a damp sponge immediately after removing the poultice to dislodge any remaining residue and surface, with additional spot cleaning as necessary using a diluted non-ionic detergent.