These are photos of before and after cleaning and touch-up redyeing of a chair and ottoman that has non-porous leather.
These are before and after photos of a commercial low level looped nylon carpet that had been neglected in a government office. Excessive soap residue build-up from spot cleaners never rinsed out. The white spot is from someone using a spot cleanercontained a bleaching agent. Nylon has dye sites, you can stain it