if the stain is fresh you may try applying kitty litter over the spot and then grind it in with a shoe.  If that doesn't work or if the stain is older, i recommend making a paste of baking soda and water and applying that to the area and let dry.

 

after using either of these methods you will want to scrub the spot with a mild detergent and water.  I use ivory dish soap.  This will also help to pull out more of the stain.  May take several repeats to get it all out.