If you just put a stain on, immediately smear it with dishwashing detergent. Wait about 15 minutes and wash. The spot formation zone needs to be erase manually , machine machine will not cope with this task. If it is not possible to wash the item immediately, and there is no detergent at hand, smear the stain with soap. Once you get home, treat the stain again, then wash.
Try removing the stain with kerosene or aviation gasoline. Rub with a cloth, as it becomes dirty, change to a clean one. As soon as the stain becomes almost invisible - wash the thing. This method helps to remove even old pollution .
Buy at the store engine oil spray cleaner. Put it on the stain, it will disappear almost instantly.
Buy any modern stain remover. Bleach is only suitable for white items. Apply it on the stain for 15-30 minutes. If the stain does not disappear after half an hour, then extend the time of the stain remover.
If you cannot cope with the stain yourself, they can help you with dry cleaning.