To clean leather parts: simply use a slightly smooth damp cloth. Do not use polish: leather used for furniture is not the same as the one used to make shoes. Avoid placing a leather piece of furniture in direct sunlight or colours may fade. Avoid placing them next to a strong source of heat like a radiator or a fireplace or the leather may dry. Do not use a rough cloth or an abrasive sponge: they could scratch the material. Do not use any aggressive cleaning agents.
To clean polyurethane parts: simply use a slightly damp smooth cloth.