The sputnik shoulder bag, made from quality materials such as nylon and polyester, make it a resilient companion. The inside is finished beautifully with opal grey lining, as is the complete inner city collection. The way of cleaning depends on the fabric and the kind of stain. For dust or non aggressive stains you can use a soft brush (i.e. nailbrush). Please make sure the brush is soft and don't push too hard so the material threads are not damaged. If this is not working try to use clean cold water and a clean towel. Make the towel a little wet and try to take out the stains. Let the bag dry natural. If the stain persists on an Inner City bag you can try hand washing your bag with mild Ph-free soap in cold water. Do not tumble dry your bag afterwards but let it dry in a natural way in direct sunlight. Please be aware the material has a water-repellent coating on top. By using the wrong soap this coating can get damaged. Also by washing your bag too hot the backing of the material will get damaged.