| abstract |
(57) [Summary] [Purpose] In order to facilitate the recycling of a substrate such as paper that has been once printed, colored or copied, a colored composition printed, colored or copied onto the substrate may be left with the color when desired. To provide a method of erasing or discoloring neatly and cleanly. [Structure] A base material such as a pen ink containing a coloring composition containing a cationic dye represented by a specific formula as a main component, an ink ribbon for a printer, a paper or cloth printed, colored or copied with a toner for copying. Is brought into contact with a solution containing a reducing agent in a wet manner so that the color is erased or discolored at a desired time without any residual color. |