So send it out to the cleaners or hand-wash immediately. There really is no such thing as spot removal. The stain is still there underneath in the fibers. Even if there's no apparent spotting, it's safest to clean or wash cashmere after each season.
Hand washing keeps it fresh, soft, clean and looking like new.
To hand wash at home, fill the sink or tub with two gallons of lukewarm water. Soak for five minutes. Squeeze the suds through the fibers, careful to avoid wringing or rubbing. Squeeze out the excess water and remove from the sink. Then refill the sink with clean, lukewarm water.