Methods, compositions and kits for masking and subsequent removal of oil,
grease, rust and other stains from a variety of rough solid surfaces,
including, but not limited to stone, concrete, asphalt, stucco brick, and
ceramic. The methods include coating the stains with an opaque or
translucent thin film of a composition that makes the stain practically
indistinguishable against the background, exposing the coated stain to
the elements, such as, sunlight, air, moisture, resulting in spontaneous
transformation, degradation and subsequent removal of the stains from the
solid surfaces. The compositions include a photocatalyst by itself or the
photocatalyst combined with at least one of, a sensitizer, a dopant, a
mediator, a co-reagent, a pigment and a binder. The role of a
photocatalyst is to produce highly reactive species or radicals and
initiate the degradation of a stain upon exposure to elements, such as,
sunlight, air and ambient humidity. Artificial light sources can be used
instead of sunlight.