When expressing the temporal change of finely structured clothes, deterioration is an imperative factor of visual simulation. Considering the complexity of their microstructures,a simple and easy way to damage finely structured clothes is required. This paper presents a novel method for modeling clothes with fiber-level details and showing their damages on a ray-tracing basis. Our particular focus is placed on washed jeans, where representative kinds of local deterioration, including cutting of fiber and color fading, affect the entire appearance of the clothes. The plausibility of the proposed method was empirically proven with several modeling and rendering experiments.