While I have never had to try it, I have heard that baking soda will do it.
Try sprinkling some dry soda on the area, brush it around and vacuum it up.
If that doesn't do it, you could mix up a baking soda/water solution and actually wash the area. I think I would probably just get the area fairly damp, then blot it up with a clean towel.
Maybe some of the Pro's will have some better ideas.