Allow mud to dry completely. Shatter the dried mud with the handle of a knife, then vacuum. For dirt, apply a small amount of a detergent solution to the spot (1/4 teaspoon detergent per 1 qt. of water) and blot with a white paper towel to work the detergent into the affected area. Continue applying detergent and blotting until spot is removed. Using a spray bottle, rinse with tap water, and then blot to remove excess moisture.