Lift away excess mud with spatula or dull knife. Let dry, then vacuum. If stain persists. Clean with cloth dampened with Ammonia-water. Use only water-based cleaning agents. Such as Resolve or mix 2 tablespoons of Ammonia or Ammoniated detergents such as Ajax to 1-quart of water. Blot the stain gently with a this solutions. Continue turning the cloth so you're always using a clean portion.