Due to the influence from the environment, microbiology and coal mining, Yungang Grottos, one of the World Heritages in China, accumulated a massive amount of pollutants at the surface of its stone heritages. The pollutants severely damage the art value and are eroding the stones. In order to remove those pollutants effectively, mechanical cleaning and chemical cleaning methods were used in the experiments. The dust on the paintings was cleaned by mechanical method, and smoke residues and suface fouling were cleaned by chemical methods. Colorimeter, microscopic imager and three - dimensional profilometer were used to detect the effect of cleaning. The colorimeter provided the colour change before and after cleaning, and the microscopic imager provided the microscopic image change before and after cleaning. TRACEiT[registered], a fully mobile system, was found to provide an easy, fast, and destruction-free measurement of the visual impression as well as the three dimensional topography in a reproducible fashion. The results showed that the methods meet the requirement of the minimum-intervention and does-not-change-historic-condition principles of heritage conservation. The method provides a new approach to assess the results of stone cleaning. In the following work, portable Raman and portable infrared technology would be used to analyze the pollutant composition and rock composition before and after cleaning to check whether the methods meet the requirement of the no-component-change-of-historic-condition principle of heritage conservation. The combined methods can potentially provide a system to more efficiently evaluate the cleaning effect.